400/512 combo

Posted By: GwaiiEagle

400/512 combo - 04/25/09 04:53 AM

I am having the block sonic checked and magnafluxed and then off to the machine shop.

I was hoping to save some bux by using as much off the old blocks I have on the new.

What exactly should I consider reusing? Can something like main caps be reused or must they be new? The oiling sytem for example? Distr. gear?

The second question is what is the most the compression can be if the gas is 91 here? I mean if I dialed the timing back for the street and used the 94 you get off island.

How much compression can I use with aluminum heads and less timing?

Posted By: RapidRobert

Re: 400/512 combo - 04/25/09 06:03 AM

Quote:

Can something like main caps be reused? The oiling sytem for example? Distr. gear?
The second question is what is the most the compression can be if the gas is 91 here?
How much compression can I use with aluminum heads and less timing?

Mainly street driven? Main caps yes intermediate shaft I'd replace. Get a new Melling std vol oil pump. Keep 3/8 pickup if the screen cleans up though they are cheap, baffle the pan. #1 You must get .035"-.040" quench which requires CAREFUL measuring as the piston rocks at TDC & clay is not accurate enough & that clearance is a small window. If quench you can run a CR in the 10's easily w alum heads & probably somewhere in the lower 10's w iron heads

Posted By: moper

Re: 400/512 combo - 04/25/09 02:55 PM

I dont like the 4.15 or larger crank in the B wedge if it's a street engine. The pistons are very short. As a result, as things wear, they will rock a lot. I would not recommend a quench tighter than .040 on them, and the rings (including the all important oil set) will not be as good for nearly as long. So the biggest I'd go is 3.915 stroke. JMO.

Posted By: GwaiiEagle

Re: 400/512 combo - 04/25/09 03:02 PM

The 470ish stroke would be fine by me since it suits the Edelbrocks heads better. I have not bought the kit yet.

Anybody else have a vote on this?

Posted By: Dcuda69

Re: 400/512 combo - 04/25/09 03:31 PM

I did a 470/400 for my a-body. Eagle 3.900 crank,Manley H-beams,Diamond pistons(small dish that mirrors the 84cc Eddy chamber)10.2:1,small Comp solid street roller. It runs easily on 93(has run on 89,oops). Great combo for a street car! Idles at 850 rpm(12" vac.)good low end and spins easily to 6k.

Posted By: 64Post

Re: 400/512 combo - 04/25/09 03:32 PM

Quote:

I dont like the 4.15 or larger crank in the B wedge if it's a street engine. The pistons are very short. As a result, as things wear, they will rock a lot. I would not recommend a quench tighter than .040 on them, and the rings (including the all important oil set) will not be as good for nearly as long. So the biggest I'd go is 3.915 stroke. JMO.

If you want longevity out of this motor the 470 is the way to go. It's one of those combos that work out really well on paper and in practice.