Arp bbc head bolts. For rush orders please contact to check availability. Quantity: -. Product Q&A. Free Shipping. 63. 135-3710: Chevrolet Big Block, w/Edelbrock head, 12pt Head Bolt Kit. Add to Cart ARP 135-3603 Big Block Chevy Iron / Aluminum Part Number: 134-3610 & 134-3710 Application: Chevy Gen III LS Series (2004 & later) 8740. Part Number: ARP-235-5601. click here to contact our customer service desk. Please call 800-826-3045 with any questions or issues. This initial torque helps seat the cylinder heads properly. When using ARP thread sealer, go with the recommeded 65 Ft/Lbs of torque. PART # Description: AR 135-3601: 6 Point Head Bolt Kit For BRODIX RR BB-O (Two Heads) AR 135-3609: 6 Point Head Bolt Kit For BRODIX Big Block For Use With Gen VI Block: AR 154-3603: 6 Point, 1/2″ Head Bolt Kit For BRODIX T1 F and ST 5. This item: ARP 4001212 12-Point Header Bolt Kit for BBC SS. So the short bolts and the long bolts all have the same spec with ARP bolts? ARP engine bolt kits come in your choice of polished stainless steel or black oxide chromoly steel bolts with 12-point or hex heads. anything before that the head bolts from GM were not stretch bolts and are perfectly fine for reusing. I would also add make sure you torque the bolts in steps. I'd like to go as high as possible without over-fatiguing anything. Chase if necessary with ARP Thread Chaser. $153. For Head Studs or aftermarket bolts CHECK YOUR INSTRUCTIONS Jun 30, 2016 · JJLT1. factor by 1. I ground down the head of the bolt, both engines. +. -lbs 32 kits found for Harmonic Damper Bolts. com. . 081" thick copper gaskets. ARP Ultra-Torque far surpasses all requirements offered by previous ARP lubricants in terms of fastener preload repeatability and performance lubricating properties. Head Studs w/12-Point Nuts. I saw a post someone had that problem and ran into that myself. This item: ARP 4001112 Hex Header Bolt Kit for BBC SS. 3/8 in. Screw-In Rocker Arm Studs: 50 ft. around $20. Both materials are nominally rated at 180,000 psi tensile strength and come in both hex and 12-point heads. Oil Pump Bolt: 65 ft. Including ARP1353706 - ARP Head Bolt Kit- Chevy Big Block Gen V Block With 502 Heads- High Performance Series - 12 Point Head. They are identified as such because ProComp/Speedmaster also sells standard length bolt and stud sets used by other brands of heads for the BBC. the gen III LS engines have one time use head bolts. Screw the studs into the block, do not apply torque. Estimated Ship Date: Jun 17, 2024 if ordered today. 50% torque (OK, let's just say 35 Ft/Lbs) then final round at specs. ARP High Performance Head Bolt Kit Big Block Chevy Late Bowtie Aluminum, World Prod. Connecting Rod Bolt: 50 ft. 1968 Camaro 468 bbc power glide 12 bolt. Apr 9, 2007 · If they are iron heads, you can remove the washer under the head of the bolt. Kit Instructions. These kits come complete with hardened parallel-ground washers. Part Number: 100-2901 Application: CHEVY/FORD HP SERIES 7/16 DIA. SKU: A14135-3607. 7/16ths diameter. 0L inline 6 (1993-98), Custom Age 625+ Head Stud Kit 24 kits found for Flexplate Bolts. #4 · Nov 21, 2005. Fastener Diameter: Fastener Tensile Strength: 170,000 / 180,000 (PSI) ( 1,171 Nmm 2) 190,000 / 200,000 (PSI) Jun 6, 2008 · ARP Header Bolt Kit Big Block Chevy P/N 400-1112. 25 RH Thread, Mitsubishi, 2. #5 · Jul 1, 2016. Warranty ARP 135-3703 BBC Aluminum / Iron Dart Cylinder Head Bolts. 625′′ long studs install along the exhaust manifold side of the cylinder head in the No. 99. 1. of torque. Summit Racing Equipment SpeedCard. The head bolt kit they recommend on their own website for these heads is ARP 135-3601 which is Find CHEVROLET 5. Automotive Racing Products Tel: (805) 339-2200 1863 Eastman Avenue Fax: (805) 650-0742 Ventura, Ca 93003 www. GM actually uses allen head bolts,If your engine was torque plate honed without them,I would not use them. Studs and bolts come either black oxide chrome moly or Stainless 300. Any time it is a specific application like cylinder heads or main caps etc, you have to go by the instructions in the kit. High Performance Series head bolts feature a reduced wrenching hex head with a wide flanged head that eliminates the need for valve train removal to facilitate cylinder head retorquing. Chase and clean the threads in the block AND the studs (they are coated with oil in the package to keep them from rusting) with a good solvent. To ensure proper thread engagement and accurate torque readings, clean ALL threads in the block. #15 · Jan 5, 2011. The hex broach in the end of the stud is designed to assist with installing/removing the studs from the block, not for applying torque. Part Number: 070-235-4321. 0 out of 5 stars 45 kits found for Rocker Arm Studs. com INSTALLATION METHOD FOR HEAD STUD KITS 200,000 PSI 7/16 inch Diameter 1. and use their lube and thread sealers. 10 gears. To ensure that the balancer is locked in position, ARP has developed these ultra strong 200,000 psi bolts that let you exert maximum clamping force. In this time wit Nov 20, 2005 · 2248 posts · Joined 2005. Package Weight: 0. The calculation of those values is solely up to the rod manufacturer. Recommended torque is equal 75% of the fastener’s yield strength. Chevy specs are 65 ft-lbs for the short bolts and 75 ft-lbs for the long. Increased material strength overcomes valve train harmonics and stress. Chevrolet Big Block Dart aluminum head exhaust bolts only, (8 pieces), hex. Flexplate Bolt - Installation. All High-Performance Series bolts are 180,000 psi tensile strength. 4 speed Muncie (M 21) May 8, 2004 · head bolts that hit header flange bbc. I use a paste with Teflon plastic threads all through the sealant to both lubricate the thread, and to seal against a water leak. ) ARP High Performance Series head bolt kits are tough. Do a first round hand tight, second round at. Main Cap Bolt (396-454, 4-Bolt, Inner and Outer) 110 ft. Cylinder Head Fasteners, Dart LS Next,12-point Head Style, Stud, Black Oxide, Kit. $384. That should give you the clearance you need. Rod Bolts - 7/16˝, 16-piece set 200-6004 Nov 28, 2009 · I just picked up new head bolts and I am getting ready to install the heads, and i happen to read the paper that came with them, It says 75 FT LBS For ARP lube an 85 ft lbs for 30 wt oil. $20 Off $250 / $40 Off $500 / $80 Off $1,000 - Use Promo Code: REWARDS ARP offers studs and bolts in a choice of chrome moly steel with a black oxide finish or stainless steel. Load the threads on the studs with the Ultra Black , screw them in and let dry. You also have a choice between hex head and easy-access 12-point designs. Jim. Feb 14, 2009 · About this item. #2 · Aug 2, 2006. Current Stock: Overview. I would suggest a set of ARP head bolts. Stage 1 torque: Begin by torquing all the head bolts to 70 ft. There's some guy on a YouTube vid that goes on and on about how f'ed up ProComp/Speedmaster studs are, thus how Jobber Price*: $122. Cylinder Head Bolts, Long: 75 ft. These kits include the bolts and washers for your engine. 2 pounds. I use either carb cleaner or brake-kleen. $20 Off $250 / $40 Off $500 / $80 Off $1,000 - FINAL DAY! Ventura, Ca 93003 www. Fastener Assembly Lubricant . Please check with your ARP dealer for actual pricing. They are both heat-treated prior to thread rolling and machining, feature an exclusive, flat, 12-point head design and larger than stock shank diameter for increased Find ARP Valve Cover Bolt Kits and get Free Shipping on Orders Over $109 at Summit Racing! ARP valve cover bolt kits are offered in a choice of chromoly steel with a black oxide finish or corrosion-proof polished stainless steel. Not Yet Reviewed. 454C. Available for a wide selection of Chevrolet, Chrysler and Ford engines, plus many Jan 5, 2009 · ARP Header Bolt Kit Big Block Chevy P/N 400-1212. Cylinder Head Bolts, High Performance Series, Hex Head, ARP 2000, Black Oxide, Same Length Bolts, Includes Washers and Lube, Chevy, LS, Kit. 1970 Chevelle ZZ572/720R. Apr 2, 2020 · The ProComp/Speedmaster BBC head casting needs the long style ProComp bolt or stud set. Part Number: 070-135-3703. Big Block Chevy with Mark IV Block and Edelbrock 60409, 60429, 60459, 60479, 60499, 60559 Heads. #9 · Jun 19, 2008. 11154 posts · Joined 2005. Share: 3. This is information that you can never find when you need it so here is a table for the ARP Head Studs, Main Studs, and Rod Bolts Torque Specifcations and Stretch Specs. ARP 235-4118. Shop for the best Cylinder Head Bolt for your vehicle, and you can place your order online and pick up for free at your local O'Reilly Auto Parts. made, but boy they're awfully expensive. Recommended Torque to Achieve Optimum Preload (Clamping Force) Using ARP Ultra-Torque ® Fastener Assembly lubricant* Note: For those using Newton/meters as a torquing reference, you must multiply the appropriate ft. /lbs. ARP rocker studs are concentric within . they make a set of 12 point short head bolts just to correct this . They are rated at 180,000 psi--15 percent stronger than Grade 8 fasteners. -lbs. Nov 23, 2005 · Buy ARP 230-7003 2307003 Oil Pump Stud Kit , Black: Main Bolts & Studs - Amazon. Shipping: Calculated at Checkout. ARP High Performance Cylinder Head Stud Kits 154-4103. 005˝, extra-large radius base offers greater resistance to flex. ARP head bolts are all reusable, even for the LS series engines. May 10, 2014 · I go by the engine manufacturer's recommendations on rebuilds which utilize OE type head bolts OR the manufacturer's recommendations when using aftermarket fasteners from ARP, etc. BUT CAUTION - DO NOT USE STAINLESS BOLTS IN ALUMINUM HEADS (unless the head threads are all heli-coiled) DISIMILAR METALS - OVER TIME THEY WILL MOLECULARLY WELD THEM SELVES 9 kits found for Oil Pump Studs & Bolts. ARP at Autosport 2024 - Jan 11-14 - Booth 8752. , LGT SS700 5-speed, 4. Representative Image. 4L/454 ARP Engine Bolt Kits and get Free Shipping on Orders Over $109 at Summit Racing! ARP engine bolt kits come in your choice of polished stainless steel or black oxide chromoly steel bolts with 12-point or hex heads. Chevrolet LS Gen III/IV LS Series, timing cover, ARP Stainless, 12pt. Also, use the ARP moly lube on the bolt heads and washers. '68 Coupe 327 Small Block. 4907 posts · Joined 2005. Head Bolt Kit 435-3603 Chevrolet Big Block Mark IV block with Late Bowtie aluminum, Iron Dart, Pro-1, Pro Top Line, & World Products iron heads, 12pt, ARP Stainless NEW KIT: 22 New Kits Announced in Our New 2024 Catalog. Jumpstart Your Next Project! Find ARP Camshaft Bolts and get Free Shipping on Orders Over $109 at Summit Racing! This week's video goes over our range of cylinder head fasteners; from OEM torque to yield bolts, ARP head bolts and even their head studs. Permatex or ARP, white Teflon "head bolt sealant" works on clean, dry threads. Shipping Weight. Head Bolt Kit. Aug 17, 2020 · 17304 posts · Joined 2010. Nov 15, 2011 · Microsoft Word - 134-3604 SB CHEVY W-23 DEG PRO ACTION HEADS HBK Installation. Jobber Price*: $286. and works on anti-freeze. They come available with a reduced wrenching hex head or 12-point head that help eliminate the need for valvetrain removal when re-torqueing cylinder heads. The bolts are part # 134-3601. 906 posts · Joined 2013. Head bolts into the block are NC threads. Listed here are the general torque recommendations for most ARP fasteners. . 2L/502 Chevy big block Gen VI ARP and get Free Shipping on Orders Over $109 at Summit Racing! Aug 16, 2016 · According to ARP's own chart your 220,000 fastener tensile strength studs require 90ft/lbs. Look for obvious defects or shipping damages. 135-3604. 00 w/ shipping . View Details See if you Prequalify. Cylinder Head Stud Kit for BBC DART Pro1 Dart 20°. To ensure proper thread engagement and accurate torque readings, clean all threads in the block. Hank. <br /> $20 Off $250 / $40 Off $500 / $80 Off $1,000 - FINAL DAY! Aug 12, 2018 · Larger Dave. 69 oz. If you have an aftermarket block all of the head 434-1501. Part Type: Oil Pan Fasteners. 435-3606. View and Download Our 2024 Catalog Now. ARP High Performance Head Bolt Kit Big Block Chevy with Mark IV or Mark V Block and AFR Casting #315/335/357 Aug 10, 2021 · Head Bolts vs Studs. Find great deals on eBay for bbc arp head bolts. Simply read down to the correct More importantly, each and every fastener is superior in strength to the OEM bolts, and also significantly better than hardware grades (even Grade 8). Report an issue with this product or seller. The heads feature a wide base for better load distribution and sealing. [5] Using an alternating or criss cross pattern, torque the bolts to 75 ft lbs using the specified lubricants in Step 4. Both are nominally rated at 170,000 psi tensile strength; substantially stronger than Grade 8 hardware. As the crankshaft flexes and twists, the balancer absorbs incredible amounts of kinetic energy. com FREE DELIVERY possible on eligible purchases Feb 18, 2010 · 71-454 said: HEY BOYS. Very common issue. HIGH PERFORMANCE SERIES - 8740 chrome moly forgings, heat-treated to 180,000 psi, tip ground flush for optimum adjuster seating. Take your pick from conventional hex or compact 12-point style heads and give your oil pan a great seal. Chevrolet Big Block Mark IV block with Brodix-2, -4, Canfield aluminum and World Products aluminum heads, hex. 99 /each. S. ”. You have a choice between conventional hex head bolts and nuts or compact, easy access 12-point designs. Cam Bolts, 12-point, Chromoly, Black Oxide, 12mm x 1. ARP studs. (95 Nm) in a crisscross pattern. Product images may differ from actual product appearance. Find CHEVROLET 7. 1-1/4" is the stock Intake bolt length for BBC and the torque spec is only 25 ft lbs but I like 1-1/2" length as well for more thread engagement. Block o-ringed. They are available in black-oxide finished chromoly or polished stainless steel. w/driver Mar 15, 2013 · Team Chevelle Members, I just recently purchased a set of Brodix Race Rite Ovals for my aluminum ZL-1 BBC (newer block) and I was looking at the length of the recommended head bolts that I purchased for these heads and they seem a bit too short to me. 830 @ 135 mph. I had bad luck with the Permatex Aviation black even with head studs. Availability Ships Direct from ARP - 3-5 Day Lead Time. 1956 210 del rey sedan 383 700r4 12 bolt posi. Clean and inspect all hardware prior to installation. ARP offers two styles of Flexplate bolts: premium grade Pro Series, with a 200,000 psi rating and High Performance, with a 180,000 psi rating. Rod Bolt Nut Style. Aug 2, 2006 · Sort by Oldest first. zdld17. OK, here goes. High Performance Head Bolt Kit Big Block Chevy with Dart Aluminum Heads (Exhaust Bolts only) Part Number: 070-135-3605. com; Instructions; Dealers; Diesel; 765 kits found for Head Studs & Bolts : Page 1 of 32 AMC 343-401 '69 & earlier w/Edelbrock heads. Head Bolts and Washers: Supplied by ARP and MANLEY. 8 pounds. ARP Intake Manifold Bolt Kit Big Block Chevy P/N 135-2002. I thought that was better than grinding through the ceramic header coating. For more information on ARP Ultra-Torque visit our website at www. 7L/350 Chevy small block Gen I ARP Main Stud Kits and get Free Shipping on Orders Over $109 at Summit Racing! ARP main stud kits help eliminate main cap walk/fretting and protect the threads in your engine block. #3 · Aug 17, 2020. A. The sheet with the ARP bolts says 65 ft-lbs for bolts with sealer (the ones that go into the water jacket, which is all of them on a BBC). Kit Instructions: We provide the stretch and torque values below as a general guide. 9. Rated 5 out of 5 by GMC kid from Piece of mind When rebuilding or building any engine it’s nice to have something you don’t have to worry about. The precision J-form threads are rolled after heat ARP. If you use a differant type sealer, go by the stock bolt torque. arp-bolts. I. doc. GM bolts in 454HO crate engine, same profile as the ARP bolts. ARP says 80 ft-lbs. Vinny. Fit type: Vehicle Specific. Part number: 4001212. Install an ARP cam bolt kit and end your camshaft timing worries! ARP quality delivers increased pre-load clamping force and assures positive timing gear register. I ALWAYS USE WASHERS the stock head bolts may be a bit short with aftermarket aluminum heads and washers. Rod Bolt stretch and torque values for aftermarket rods are determined by the rod manufacturer. 135-3601 - ARP High-Performance Series Head Bolt Kits is rated 4. TH 400 w/brake. anyway, i called arp . Stage 2 torque: Next, increase the torque to 100 ft. Jan 28, 2018 · I like that ARP fasteners are U. View Now. World Products doesn't say. i'll have mine next week. Fastener Style: Bolt. Because the BBC stock blocks all have head bolts that go into the coolant passage they have to be sealed. This item: ARP 135-2002 Intake Bolt Kit for Big Block Chevy. I'd probably buy ARP for critical stuff like rod bolts/capscrews and main bolts and be fine with Elgin, or Manley for the rest. Didn't need to take off much to make it clear. See more product details. Part number: 4001112. $139. ARP head studs have NC threads on the end that goes into the block but NF threads are at the top that are torqued with a nut. Part Number: ARP-154-4103. 3, 6, 11 Then install the flexplate onto the crankshaft and tighten the bolts hand tight. ARP Cam Bolts 107-1002. › See more product details. and run a cleaning tap through the blocks threaded bolt holes. be aware that head bolts enter the block coolant passages, so if you failed to dip the bolt threads in sealant when they were assembled, through the heads coolant can seep up along the head bolts, into the area under the valve cover. Mar 2, 2010 · NA 540 BBC Dart CNC-355's 8:90 @ 151 1250 P/S Dominator on M5 3130 lbs. ARP High Performance Series Cylinder Head Bolt Kits 135-3609 Cylinder Head Bolts, High Performance, Hex Head, Chevy, Big Block, with Brodix Aluminum Heads, Kit Part Number: ARP-135-3609 160 Customer Reviews. Connecting Rod Bolt: 67-73 ft. ( 1 ) Estimated Ship Date: Jun 17, 2024 (if ordered today) Free Shipping. 50. Dart Aluminum heads. [1] Please check the part-number(s) for your Dec 20, 2012 · How high can I torque my head studs to try to keep from pushing out gaskets, etc? Merlin Iron block. This torque level further secures the cylinder heads. Rob, That only applies if the stud is being used in a "generic" application. Jan 5, 2011 · 683 posts · Joined 2005. 114-3605: AMC 19 kits found for Cam Bolts. Long Head Bolts 75 - 80 Ft/Lbs. Outside the United States, the prices may be higher due to transportation costs and import duties. Click image to zoom. Find all of the cylinder head bolts, studs, and kits you need to complete your engine repair or rebuild job. 4L/454 ARP Connecting Rod Bolts and get Free Shipping on Orders Over $109 at Summit Racing! ARP High Performance Series head bolt kits are tough. The nuts feature a wide base for better load distribution and sealing, while the compact head is easily accessed. NOTE: To be used ONLY with ARP’s patented Perma-Loc™ adjusters. Find CHEVROLET 8. NOTE: The 6. Summit Racing has a massive selection of header fasteners in stock. 356. Part number: ARP-135-2002. Lowest Price Guarantee. 1 day ago · ARP High Performance Series Main Bolts 134-5001 Main Bolts, High Performance Series, 2-Bolt Main, Large Journal, Chevy, Small Block, Kit Part Number: ARP-134-5001 Enter your kit number in the field below and click “Submit. Oct 12, 2013 · Removed heads and all bolts are ARP. I have always heard 65 lbs. that seems HIGH to me. Cylinder Head Studs, High Performance, Chromoly, Black, Hex Head, Offenhauser Ford Flathead Head Type, Ford, Mercury, Kit. Do not use oil on Chevy heads, they need sealer as the bolts go into the water jackets. We would like to show you a description here but the site won’t allow us. It may be an over kill on some stockers but their are worth their money. Oct 31, 2023 · High Performance Head Bolt Kit. 75 pounds. Part Number: ARP-234-3602 5. Hex. Doubt that your heads will require them but if you use them , be sure you use sealer on the threads into the block especially in the water jacket block Shop header bolts and studs from Stage 8, ARP, BBK, Kooks Headers, Percy’s, Hedman, and more. ARP-bolts. Come See Us at the 2023 PRI Show - Dec 7-9 - Booth 801. Updated engine torque spec booklets are usually available for free, or a nominal cost from gasket manufacturers such as Fel-Pro or Victor-Reinz. Threads are just an inclined plane. Short Head Bolts 65 - 68 Ft/Lbs. 73. 6 out of 5 by 5. Install the head gasket and cylinder head. This would be for the short bolts on that bottom row. They include studs made from 8740 chromoly steel and heat-treated in-house to 190,000 psi tensile-strength rating. Big Block Chevy 427 ZL1 Limited Edition. Therefore, torquing a bolt to say. Special features include 1/4˝ thick, wide area washer and Manufacturer of fasteners found in engines and drivelines, ranging from OEM replacement parts to specialty hardware for racing applications. ARP bolts in stock 396 heads. 64. Main Studs, 4-Bolt Main, Dart Big M Block, Chevy, 454, Kit. Dart says 70 ft-lbs. You have a choice of two premium quality materials and finishes. 2. Intake Manifold Bolts (Cast Iron Head) 25 ft. ‘70 SS. Cylinder Head Bolts, Short: 65-68 ft. Jun 3, 2006 · ARP head bolt torque spec. $5390. 10’s. hooker 2455 w/ edelbrock rpm heads and arp bolts. Shop with confidence. Inspect all hardware prior to installation. Didn't find the kit you were looking for? Chevy V8 hex. Heads grooved. ARP Main Stud Kits 235-5601. IMO, studs are always better than bolts. Sep 27, 2009 · Simple and multi-purpose. don't remember if it was #2 or #3. (135 Nm) in the same crisscross pattern. Includes appropriate fasteners for your application. 12pt Head. 7/16 in. Two slow cars with engines and stuff. Vendor Part Number. $4021. btw read this. $120. Please contact the rod manufacturer using the chart below for the exact values for your bolt and rod combination. Rod Bolt Head Style. Package Weight: 1. $49. California Residents Only: ⚠ WARNING: Cancer and 1 day ago · ARP High Performance Series Cylinder Head Bolt Kits. ARP performance oil pan bolt kits are just what the doctor ordered to cure leakage. Special Order. 0L DOHC 4G63, Kit. Ships on 10/31/23. Big Block Chevy Head Bolt Torque Specifications. ARP 135-3701 - High Performance Head Bolt Kit Big Block Chevy 396-402 Jun 19, 2008 · 1975 posts · Joined 2008. Toyota Supra 2JZGE/GTE 3. 0 out of 5 stars Studs are manufactured with a unique nut-starter nose that helps prevent cross-threading. com or call 1 800-826-3045. ARP High Performance Series head bolt kits are tough. $4344. (opens in a new window) * The prices listed on this website are for estimating purposes only. Head Stud and washer mounting locations May 20, 2024 · Find CHEVROLET 7. best run to date. Important: if you have an aftermarket connecting rod with an ARP bolt, please use the chart below to contact the rod manufacturer for the stretch/torque value. lbs. #2 · Aug 12, 2018. 135-3711: ARP PTFE thread sealer 1. Merlin, Iron Dart, Pro-1 and Pro Top Line Heads. For ARP’s high-strength, fatigue-resistant bolts, head studs, fastener kits, and other hardware, Summit Racing has the lowest prices and widest selection. Feb 9, 2008 · Hi Tony, I know some that don't clear, Dynomax. Pace Performance offers the best pricing on products offered by ARP. ARP Pro Series Cylinder Head Studs 234-4341. It looks like a blue RTV was used on lower portion of bolts and anti sieze up top. 12 Bolt w/ 4. 4. $253. 100-9904: ARP's High-Performance Series Head Bolt Kits are available with a reduced wrenching hex or 12-point and wide area flanged head that eliminates the need for valve train removal to facilitate cylinder head retorquing. Head Studs w/12-Point Nuts Big Block Chevy 427 ZL1 Limited Edition. 0 Small Block Head: AR 200-8506: 3/8 Head Stud Washer For ARP. Maybe someone with more knowledge than me can jump in on my thoughts on this subject. hc yc hz oq qa hz lv mc yx um