I just got a running 4 bolt main 350 from a guy for free. The problem is, is that it's a one peice seal block. I was told by a couple of racers that one peice blocks are junk because they leak and they're much weaker than a two peice block. Is this true? I'm sure a 1 peice block is OK for a street motor, but will it work as a 550 HP race motor ? Should I junk this motor and find a two peice one ?

Thanks.

 

No! Tell those supposed racers to get off the bench and get thier hands in an engine before opening thier flaps. Once piece block is actually stonger in a sence, its newer and is less prone to leakage.

 

On the 1 pc. RMS Stronger seems to be argueable subject, But they do seem to be much less likely to leak!

 

Strength is the same between the 2.

There's alot more aftermarket cranks available for 2-piece. There are very few real race parts for 1-piece; there's some street stroker stuff, that's about it.

The 2-piece seals just fine, when properly assembled. The 1-piece is both considerably easier to get to seal properly and also much faster to assemble; that's the real reason the factory changed, is ease of assembly. It's about 10,000 times easier for an assembly-line worker to just bonk a lip seal into a slab of metal and than for another to bolt it on as the engine rolls along the line, than to fool around with the 2-piece thing on the engine line.

Probabaly your racer friends are just repeating the same nonsense they heard from some other racer at the track, and have no facts to back up any of it.

A 550 HP 350 is hardly a race motor; that's just a nice warm street motor, easily attainable with a stock block. A one-piece block should be fine at that level. At that moderate power, I'd be alot more picky about the rods and rod bolts than the block.

 

I'm allready planing on better rods. How do you think the stock crank will hold up? Should I go with an aftermarket crank also?How many RPM's can a stock crank take, 6500 maybe 7000?
I've got a set of 230cc DART Iron Eagle heads w/ 2.05" and 1.60" valves lying around, are thease going to be to big for a 350 ?

Thanks.

 

It won't.

Yes.

A stock crank will go that many RPMs, a few times, usually; no telling how many though. It might last hundreds of passes, it might let go the first time. No way to predict that. A good racing crank will do it season after season, no risk or problems.

Those heads should be fine, as long as you use plenty of gear (and stall if it's an auto), and an intake that will match comfortably to a 1206 gasket. With that big intake valve and little exhaust valves, you should definitely run a split-pattern cam. I think a solid roller is going to be what you'll need to really do it up right. Those heads should already be prepped for 1.550" springs, at least my Dart 200s are. I'd expect you'd want a cam somewhere in the low 260s of intake .050" duration and low-mid 270s of exhaust, and you should aim for at least .570"-.580" of lift on both with the combo of cam and rockers.

edit: http://www.competitioncams.com/catalog/066_067.html look at the 300BR-6