aluminum vs. steel main caps 392 hemi

Posted By: Hemi_Joel

aluminum vs. steel main caps 392 hemi - 03/14/14 04:56 PM

HI, I'm building a 392 hemi using a 1958 block, putting in a 5/8 stroker crank. (4.525") This moter will have steel rods and high compression, and I want to build it to hold up to drag strip thrashing and street cruising. Bottom end strength is a big concern. I plan to convert it to 4 bolt mains. I have talked to a handful of reputable machine shops about using aluminum main caps, and I get a different opinion from everyone. Some say do it, some say never do it, others don't have much opinion.
So what are the pros and cons of the aluminum vs steel caps? Besides weight?

Thanks, Joel

Posted By: Dragula

Re: aluminum vs. steel main caps 392 hemi - 03/14/14 05:25 PM

Interesting post...

There was an article a while back on building a mega hp "whale motor" for nostalgia racing...

Can't find it though. I beleieve they said the +40 bottom end was good to go, but I am sure that wasn't with as big of a stroke as your planning...

What would concern me is what rpm are you going to max out at...With the stroke you are planning, my thought is the cylinder wall on the thrust side will have to take the greatest load...And that is where I think things get interesting.

Me, if it were my engine, Pro-Gram billets would be in it again...But if you want a better opinion, call my engine builder as he has assembled a number of these early Hemi's.

Ron Farley
716-799-5588

Posted By: Cab_Burge

Re: aluminum vs. steel main caps 392 hemi - 03/14/14 06:25 PM

Which block are you using, standard, RR or A-1? the standards have a open slot between the mains and the bottom of the cylinders, not a good choice for high HP or high RPM

The RR and A1 will have those initials cast into the top of the lifter valley and the edge of the deck, usually on the rear passenger side, thier supposedily better castings with more meat in the block

Let us know what you find

A lot of the old time racers like to use the 354 blocks to build do to the problems with the 392 blocks

the 1955 and 1956 heads are better also, better port angle to the valves, just install the size valves you want to run in them

Posted By: dogdays

Re: aluminum vs. steel main caps 392 hemi - 03/14/14 06:39 PM

This is hearsay, but the 1958 blocks supposedly have less support to the lifter bores and can actually fail if you use too big a camshaft. Something to check out.

R.

Posted By: quickd100

Re: aluminum vs. steel main caps 392 hemi - 03/14/14 06:53 PM

Joel; Call Jim Swedberg at 701-775-0113. He's raced and built the old hemis forever and probably forgot more about them then we'll ever know. May have a few old speed parts for them too.Dave

Posted By: ChrgrCuda

Re: aluminum vs. steel main caps 392 hemi - 03/14/14 08:08 PM

Looking forward to seeing the outcome of your project. Very cool!

So what are some flow numbers from those early heads?

Posted By: Handygun

Re: aluminum vs. steel main caps 392 hemi - 03/15/14 12:14 AM

Bob Mckray, Gene Adams and a few others have gotten 370 on the intake out of the 555 heads. If I could do my 392 again it would be a stroked 354, Stiffer block,smaller package. Big Al's toybox has a run of Moroso pans in stock. Stud everything and plan on buying adapters for everything. My timid hydraulic 392 pushes my 4300 58 Ply wgn to mid 13's through manifolds and a 518. Good luck Joel and great X BTW.

Posted By: MR_P_BODY

Re: aluminum vs. steel main caps 392 hemi - 03/15/14 12:50 AM

Quote:

Bob Mckray, Gene Adams and a few others have gotten 370 on the intake out of the 555 heads. If I could do my 392 again it would be a stroked 354, Stiffer block,smaller package. Big Al's toybox has a run of Moroso pans in stock. Stud everything and plan on buying adapters for everything. My timid hydraulic 392 pushes my 4300 58 Ply wgn to mid 13's through manifolds and a 518. Good luck Joel and great X BTW.

Is that engine(back mount area) set up for a BB trans

Posted By: Hemi_Joel

Re: aluminum vs. steel main caps 392 hemi - 03/15/14 01:21 AM

Its an A1 block, but still the web between the main bearing bore and the pan rail is quite thin.
I'll have to take a close look at the lifter bores. Dave, thanks for the referral, I'll give him a call.

Aftermarket heads can flow 360+ on the intake...

I bought this billit crankshaft off ebay, it turns out that the seller was John Calvert and he said the crank checked out good. Today I dropped it off to be magged anyway, just to be safe before I start the build.

Posted By: Hemi_Joel

Re: aluminum vs. steel main caps 392 hemi - 03/15/14 01:24 AM

Quote:

Bob Mckray, Gene Adams and a few others have gotten 370 on the intake out of the 555 heads. If I could do my 392 again it would be a stroked 354, Stiffer block,smaller package. Big Al's toybox has a run of Moroso pans in stock. Stud everything and plan on buying adapters for everything. My timid hydraulic 392 pushes my 4300 58 Ply wgn to mid 13's through manifolds and a 518. Good luck Joel and great X BTW.

How much stroke will a fit in a 354? I'm not married to the 392 block, but since I already have the 4.525 bilet crank, I want to use it.

Posted By: Cab_Burge

Re: aluminum vs. steel main caps 392 hemi - 03/15/14 04:45 AM

Quote:

Quote:

Bob Mckray, Gene Adams and a few others have gotten 370 on the intake out of the 555 heads. If I could do my 392 again it would be a stroked 354, Stiffer block,smaller package. Big Al's toybox has a run of Moroso pans in stock. Stud everything and plan on buying adapters for everything. My timid hydraulic 392 pushes my 4300 58 Ply wgn to mid 13's through manifolds and a 518. Good luck Joel and great X BTW.

How much stroke will a fit in a 354? I'm not married to the 392 block, but since I already have the 4.525 bilet crank, I want to use it.

Man, that is a long stroke for one of those motors

Is it a blown fuel application with the center counter weigts or no center counter weights? What size main and rod journals is it

I had a Reath Auotomotive welded 4.375 chrome stroker crank at one time, never got around to using it

As far as the original question on which material main caps I would use aluminum on the street and steel for a race only, if I was going to use a stock type block that is

I've dreamed of trying to use a Dononvan 417 aluminum block on the street, they (Donovan) said don't do it

Posted By: Hemi_Joel

Re: aluminum vs. steel main caps 392 hemi - 03/15/14 05:45 AM

It has 8 counterweights.

Posted By: Handygun

Re: aluminum vs. steel main caps 392 hemi - 03/15/14 04:10 PM

You run an adapter to push the trans back to clear the "extended" flange on the crank, then run the A motor trans. I don't know how long of a stroke you could run in a 354 but I'm with Cab on the apprehension on running that much stroke. Gene Adams was developing a siamesed iron Chrysler block that could really take advantage of all the aftermarket parts with out so much risk of grenading a 50+yr old collectors item block but I haven't heard much about it lately.My car doesn't even begin to approach the level the level of massaging a FAST car has, But to me It's impressive of how well it runs with minor cleanup on 354 heads, lightwt pistons and rods,220/.480 cam and an alum copy of the oem single 4 intake.