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By one piece at a time - 3 Years Ago
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I am needing new bolts for heads and main caps for 292 block. Talking to Ted he said the ARP bolts was overkill. He says get a good grade 8 bolt instead. A 4 year old post on this site indicates that caterpillar Grade 8 were the best to get. Does any one know what the part numbers would be for Cats bolts and washers or What size bolts do I need to ask for as mine are with the block in the machine shop to many miles away to go measure if I can help it. Any info is appreciated. Thanks
Duane
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By Dobie - 3 Years Ago
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My '55 Merc chassis parts catalog lists the long head bolts as 7/16"-14 X 4 1/16" , qty 10, and 7/16"-14 X 2", qty 10 for the short ones. For the main caps you need 1/2"-13 X 1 3/4", qty 10. I skimmed through the Cat bolt selection online and found some that are close but no exact match. Good luck and let us know how it turns out.
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By one piece at a time - 3 Years Ago
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Thanks That helps. I was told that washers were OK to use as long as they were the same grade as the bolts.
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By Dobie - 3 Years Ago
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Cool. I'm about to go through the same exercise. I had checked with John Mumert since he lists an ARP head bolt kit but on speaking with him he said ARP has quit making the short ones.
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By Joe-JDC - 3 Years Ago
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Before ordering these bolts, you had better check the long bolt lengths again. Four of them are longer than mentioned, and 6 are long. The 10 short ones are the same length. Joe-JDC
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By one piece at a time - 3 Years Ago
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Thanks Joe will do .
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By Dobie - 3 Years Ago
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Joe-JDC (2/26/2021)
Before ordering these bolts, you had better check the long bolt lengths again. Four of them are longer than mentioned, and 6 are long. The 10 short ones are the same length. Joe-JDC
Those specs are from the '55 Merc chassis parts catalog. I realize the long bolts became different lengths in '56, I believe. Don't know if the '56 bolt lengths are backwards compatible with a '55 with '57 heads.
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By 2721955meteor - 3 Years Ago
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head bolts 2longones 4and 3/8
3 short longs4and1/8
5 short2and1/8. measured from end of threads tosholder of head
I used cat grad 8s they are a better than original, but the short bolts are prone to breaking due to the heat cycles memory has it I needed to trim thecshort longs, or you could use some hardened flat washers. well you are at the cat house the 3/8 grade 8 withe cat hardened flats is the only way to go on exhaust, never come loose in my 292. main cap bolts cant help you I have a system to give better results having no rear seal aria leaks. a precision plate that presses on the raised dimples of the pandas well as thicker pangasket of denser material. if you ar interested send me your email and will forward pictures(ct1940@shaw.ca
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By KULTULZ - 3 Years Ago
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Just wondering, are the ARP cap screws considered overkill or are too expensive?
GRADE 5 will not suffice for a stock rebuild?
Here's charts if they can help anyone -
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By one piece at a time - 3 Years Ago
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Thanks For the chart. It confirms the lengths for me. I didn’t think the 1 3/4 main cap lengths sounded correct. I have been on the Internet researching grade 8 vs ARP bolts and hears my thoughts. Grade 8 bolts have tensile strengths in the 120,000 psi range and cost $2. To $3 maybe $4. ARP bolts are in the $4 to $8 range and are in the 180,000 psi range and up. The harder the bolt the more brittle and more likely to break instead of bend. Harder bolts fatigue faster also according to an article in engine builder . I called John Mummert yesterday he said ARP didn’t stop making the short bolts they were just out of them. He didn’t know when they would be available again. I asked his opinion on grade 8 vs ARP and his response was “ I’ve heard of people doing that “ I found a place on line called Allensfastners.com who sells both ARP brand and other type and grades. There is not an exact match in lengths so either one will require washers and or trimming.
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By DryLakesRacer - 3 Years Ago
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I like using grade 8 thick washers on head cap screws and studs for sure. I’ve always felt the washer spread out the fastening of both head and main caps. If I can get studs it’s what I prefer. ARP doesn’t have the specifically for my race engine but does sell a length I can use. As the engine has a shaft rocker arm system also I do need to remove about 1/4” from the fine thread end for clearance. ARP doesn’t make it ez to look up individual bolts or studs as I remember.
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By KULTULZ - 3 Years Ago
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DryLakesRacer (2/27/2021)
I like using grade 8 thick washers on head cap screws and studs for sure. I’ve always felt the washer spread out the fastening of both head and main caps. Agreed. I am afraid of the cap screw head galling whatever it is tightening against, especially aluminum, resulting in a false torque value. You would need flat ground washers, not stamped. Here is another fastener source if it helps anyone - https://www.mcmaster.com/screws/hex-head-screws/
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By one piece at a time - 3 Years Ago
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What’s your opinion of using a flange bolt on heads and cap bolts with washers? The flange bolts from ARP are close to what’s needed and washers will put me within a 1/16 in most cases. Minimal trimming. The Allens Fastners site list the bolts in progressive lengths. I give up trying to find caterpillar bolts as too complicated and time consuming.
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By DryLakesRacer - 3 Years Ago
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If they are grade 8 and do not have cirations (sp) on them I don't see a reason not to use them if they fit your needs. For a standard use engine, not racing, a good quality grade 8 should be a viable option if you do not have originals,
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By 2721955meteor - 3 Years Ago
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grade 8 cat bolts are designed to be flexible and will be better than harder and more strength but do not flex as well. this is especially critical on head bolts with extrerm temp changes. the ford shortrs on ys where more likely to break as shorter bolt has less ability to flex. also cat grade 8 have large head.
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By one piece at a time - 3 Years Ago
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I think I have it figured out. I took another stab at the caterpillar parts site and found lengths that will work with minimal trimming and using washers I will go to the Cat dealer next week to see if they have what is listed on the website. I’ll post what I find out .
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By Ted - 3 Years Ago
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KULTULZ (2/27/2021)
Just wondering, are the ARP cap screws considered overkill or are too expensive?
GRADE 5 will not suffice for a stock rebuild?
My ‘overkill’ statement simply comes as a result of the cost of the ARP versus grade 8 bolts being purchased elsewhere. The key here is the quality of the bolts as bolts being made overseas may not be the actual grade as they are advertised as being. I do use a lot of ARP fasteners regardless of the cost simply due to the known quality of those fasteners.
I attribute most head gasket issues with the Y resulting from the use of grade 5 and grade 6 head bolts. Those bolts are notorious for not holding their torque for the long haul. Possibly stretching over time? While the use of steel shim head gaskets does contribute to the need to re-torque the head bolts after initially running an engine, the stock grade five and six head bolts simply reinforces that need. I have zero issues with grade eight head bolts in regards to long term head gasket seal so I simply make it a point to use grade eight head bolts on most applications. Likewise I do not find it necessary to re-torque composition head gaskets when used with grade eight head bolts.
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By KULTULZ - 3 Years Ago
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My ‘overkill’ statement simply comes as a result of the cost of the ARP versus grade 8 bolts being purchased elsewhere. The key here is the quality of the bolts as bolts being made overseas may not be the actual grade as they are advertised as being. I do use a lot of ARP fasteners regardless of the cost simply due to the known quality of those fasteners.
I meant no disrespect if taken.
That's is what I was wondering if the ARP cost was a factor in a simple stock rebuild. And 10-4 on off-shore counterfeit fasteners. The airline industry had that problem some years ago if you remember and it trickled down to automotive, incl FORD.
Now weren't factory fasteners of that period GRADE 5? Just wondering and I agree with the GRADE 8 upgrade.
I can't afford to pi$$ you off as I learn so much from you ... 
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By Ted - 3 Years Ago
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KULTULZ (2/28/2021)
I meant no disrespect if taken. That's is what I was wondering if the ARP cost was a factor in a simple stock rebuild. And 10-4 on off-shore counterfeit fasteners. The airline industry had that problem some years ago if you remember and it trickled down to automotive, incl FORD. Now weren't factory fasteners of that period GRADE 5? Just wondering and I agree with the GRADE 8 upgrade. I can't afford to pi$$ you off as I learn so much from you ...
No offense implied or taken. I’ve come across at least four different head bolt grades during the course of Y production. The grade eight versions do tend to show up more on the 1963-64 truck engines. Those I’ll reuse but the rest I treat like ‘torque to yield’ hardware and discard. Here’s a picture of what I currently have laying loose as far as oem Y head bolts.
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By one piece at a time - 3 Years Ago
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Update and what I ended up with. Bolts from the Cat dealer was more problem than I wanted to deal with. They didn’t have what I needed in stock but would order them but would be charged shipping. I went on line and found ARP 12 pt bolts and champherd washers from Summit Race. FreeShipping.For Dobie and anyone else needing info here is what I bought. Main bearing bolts 3” # 617-3000 . 2 packs of 5 @$22.99 & 1 pack of 10 washers 1/2”# 200-8533 @$9.99 For the head bolts 1 pack of 5 4 1/2” #645-4500 @$27.99 (there will be 1 extra)2 packs of 5 41/4” #645-4250 @$26.99 (4 extra) 2 packs of 5 of 21/4” # 645-2250 @$17.99 and 2 packs of 10 7/16 washers # 400-8539 @$12.99 along with some assembly lube@$7.99. All totaled $146.92 . the longer bolts were back ordered but everything else got to me in 2 days. There may be some trimming but not much using the .120 thick washers . I hope this helps someone. I spent several hours researching.
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By Dobie - 3 Years Ago
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Glad you found something workable. I had a feeling Cat would be a PITA, especially for anything out of their ordinary. The machinist who rebuilt my heads ordered me a set from McMaster-Carr. The long bolts are a 1/16" short at 4" even but since he took 0.007" off the heads to make 'em flat the 4" bolts will be OK.
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By charliemccraney - 3 Years Ago
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I used a stud set for Mopar, small block, to get the stand off studs for a windage tray. They are a little longer than the main studs I got from Mummert a long time ago. Mopar main bolts might work but because of that extra length, you do want to check to ensure that the bolt doesn't bottom out or block off oil passages before proper torque can be applied.
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By one piece at a time - 3 Years Ago
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Well I will have plenty of washers. I didn’t know ARP included the washers with the bolt packages. You don’t need to buy the washer packs I listed before
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By ogasman - 3 Years Ago
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Anybody know what grade the "FT" bolts are in Ted's picture?
Paul
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By Ted - 3 Years Ago
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While Paul contacted me directly regarding what the ‘FT’ designation means in relation to the grade value, I was not able to help. While the grade five and grade six bolts do have slightly smaller shanks than the grade eight bolts, the ‘FT’ bolts do have the same shank size as the grade eight bolts. Based on that alone, it’s easy to surmise that the ‘FT’ bolts are grade eight without any additional information or testing to point elsewhere. Nowhere in my literature is there any reference to what the ‘FT’ bolts are in regards to their grade values. Any additional information regarding this is welcome.
What is interesting is the recommended torque values for the various grades of bolts. The 716" grade five and grade six bolts are being pushed well beyond the factory head bolt torque spec recommendations based on the following chart.
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