Technical 354 hemi main caps

I'm building a stock stroke, 6/71 blown alcohol 354 hemi for a short wheelbase altered. Running a fully filled block, aluminum rods and am not sure on main caps yet. Starting to lean towards hot heads billet steel splayed caps after finding out stanke doesn't really make 354 aluminum caps and I don't want to run a girdle, have heard mixed opinions on aluminum and steel caps. Looking for bottom end combos and overall advice from people with experience with early hemi's. If you're going to tell me to put a Chevy motor in it, don't waste your time typing.

 

We have made 2-bolt billet caps for project engines in the past but personally not fond of the splayed bolts.
We have even put blown engines together with stock caps and studs for street use and never had an issue.

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Why are you not fond of splayed caps? It is strictly a race car. Going to spin it around 7,500-8,000rpm.

 

From a structural standpoint I question exactly what they are doing and how well they are doing it.
If the crank decides to 'exit the building' it will likely be headed straight down-away from the main webs and the support of the bearing/bore. Your splayed bolts will do little, or nothing, to even delay this procedure as they will simply bend. Not much shear, not much tension, lotsa bending.
Do they somehow tie the sides of the webs together? I don't see it. Maybe you do.

IMHO, splayed bolts are just another design element that the shiverlay folks brought with them when they decided to play with an EarlyHemi. MaMopar has used 4-bolts caps but not in this fashion.
Your money; your parts; your results may vary.

 

Thanks 73RR. Interesting theory. I always read your posts and enjoy!!

 

Interesting discussion. What about 4 bolt caps that use straight bolts?

 

I think TR Waters and Gene Adams did some experiments on a 354 for the Engine Masters Challenge and found that a girdle help on the main cap walk. This was my 392 from last year and it hit over 9K many times without issue. Its not blown though. Check with @402BOSSMAN also - he works close with Gene Adams.

 

i run the hh caps and have had no problems.

 

my uncle built a girdle in 1958 for a 331 block - it lasted a few years maybe about 1962....just missed my chance at getting it in about 1994....when we started to talk.....

 

100 ways to skin a cat and the cat he don't like none of them. Lippy

 

DogPatch.........I understand what the girdle setup is for however what is the reason for the extra set of nuts & bolts on the inner edge of the oil pan rail.......also why the extra piece of what looks like 1/8th plate along the pan rail.........this appears to go under the nuts that I referred to.........I appreciate seeing all these pics and details of what people do to help engines live in high hp situations........thanks for taking the time to post the pics.......regards, Andy Douglas

 

Andydodge....that's a crank oil scraper.

 

What's the application? Do you run a girdle as well?

 

MaMopar used 4 'vertical' bolts on the 340 TransAm engines, and the obvious cross-bolt system on the 426Hemi (IDK what is used on the more modern stuff).
The basic issue is one of initial design. If the block and all of its bits and pieces was designed with the splayed bolts as part of the package then, no doubt, it/they will do what they were intended to do.
In an EarlyHemi the splayed bolts are usually quite small and they go through a rather thin casting area and often end up in the water jacket. That is not where I want them.
As racer-x indicates, he has had "no problems". But, has the install actually provided any benefit? There is no way to quantify the results.
If you (anyone out there) 'think' that they will help and if you don't mind paying to play then perhaps peace of mind is worth the cost. If there is a failure of some sort then you can do a forensic analysis and try to determine the chain of events but, hopefully, your engine has a long and happy life. These suckers are not cheap to build.

For a serious engine package I'd use Tom's plate or build a full girdle.

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Seems to me the chevy splayed caps were much larger and the block machined so the cap registered down into the main webs and the splyed bolt locked them into place. It isn't as if they just drilled a hole at an angle and shoved a bolt in there. The 354 may not have meat in the right areas to do this, I can't say. I can tell you it works good on a SBC.

 

For aluminum main caps try Dave Dewars at VRE/precision Machining,
Princeton, MN (612)839-4275

 

This is a 331 that Keith Black did back in 1968, it was injected nitro...

 

I can say one thing no matter how you build it, If you are going to run a stock crank, send it to Henry Velasco, you can have him offset grind the crank and use BBC rods in it , lots cheaper. Also have the flywheel bolt holes drilled and tapped next size up, he will nitride it and straighten if needed and the price will make you smile. Plus he has been doing Hemi cranks for a LONG time. JMO. Oh yeah, throw an extra couple keyways in that crank snout. Lippy

 

Great shot Marty, that looks eerily familiar. Lippy

 

I plan to use my stock crank at first for budget reasons, maybe 30-40 runs. Then buying a billet crank

 

Sounds like if you are diving in the block work it would be stopping short not to do the crank also.

 

I get what you're saying. Not really too confirmed about the crank yet. I'm building the car myself with a friend and I need to get the mains done so I can center my bellhousing on the crank and finish my motor plate, and mock up the driveline so I can make a seat and finish the steering stuff and make a rollcage. I will look into cranks when the time comes. It might not be worth it to get work done to the stock crank vs. buying a billet one already done. Are the billet cranks generally keyed or splined?

 

I understand now.
Sounds like you have lots of work and a lot of fun in store for you.

 

I don't think you need a billet crank. JMO. Good condition stock steel hemi cranks are a good piece. If you can run injected nitro with one you sure can run blown alky. Again just my opinion that and 50 cents won't get you a cup of coffee. Lippy

 

BTW what are you gonna run for a trans, clutch ect...?Lippy

 

I just looked at your profile . Your a crew chief on a funnycar and your asking us for advise. I have been around nitro and blown stuff for a long time and I find that rather odd. Lippy

 

R.Pope........thanks for the info re the crank oil scraper........makes sense now......andyd

 

We consider it more of a "car chief". I don't tune the car. I am the only guy near the home shop, so I've done everything there is to do on the car (cam timing, valve heights, spring pressures etc.) and I do the clutch at the race track and start the car and drop the body etc. and all I've worked with is brad and aj 426 stuff. Which as you know don't have the structural issues an early hemi does especially being that the main sits down inside the block and has cross bolt mains. I'm here to hear from people with early hemi racing experience. Peter ran a Chevy powered a/a in the 70s and a few different ta/fc's throughout the 80s and was the second in the 5's in 1989. He build his nostalgia nitro car about 8 years ago. I'm getting a clutch from work and was going to run a 2 disk 10" aluminum glide clutch and I have a lenco 3 speed for the car. The rear will be a strange ultra case with 9 and a half inch gears and most likely 35 spline axles. The crank I have needs checked, it's a .010 under stock crank. A friend of my bosses steve Boggs told me when they used to run them you just can't cut the crank down too much or you'll get into the soft material and it wants to grab and spin bearings.

 

Sounds like a good combo a two disk would be about right. I think if the crank was re-nitride you would be ok. We had splayed aluminum main caps on our A/F 354, no issues. After a good bang it was still in there, the crank was cracked but the bottom end was still there. lol. I am of the opinion the 354 block is way stronger in the main web area than a 392. My brother Leon would be the guy could maybe help you out. You probably have met him somewhere. Lippy

 

I'm familiar with frank and the crop duster. I helped make the monza body and mount it to his chassis. Can't say I know him real well though. I talked to stanke last night and it sounds like he is making the center three but doesn't sell enough to have interest in running a few rears. Probably going to run steel front and back and aluminum centers with a girdle.