I plan on rebuilding my engine using forged pistons, stock crank, aftermarket rods. I originally planned on building up a 385 with LE3 heads, Scat crank, etc. However I had some things came up and I had to end up selling all of the parts I had accumulated for the 385 build, except the used SRP 4.040" pistons (part#138090). So now that everything is paid off and behind me now, I plan on rebuilding my engine again, but on a little tighter budget, to get the car on the road again, so I decided to go 355 with stock crank, LE2 heads (used if I can find any), etc.

My question is this, the SRP pistons, while designed for 3.75" stroke with 5.7" rods have a compression height of 1.425". Doing some calculations, I determined that with the stock crank, a 5.85" rod, and 9.015" deck height, that these pistons should theoretically work in a 357 build going .040 overbore. Am I correct to assume this? If so, it would save me some money on my rebuild as I would only have to buy forged rods, new rings, bearings for the bottom end.

I would like to find some lower priced I-beams, but other than the VERY pricey ones like Oliver, Lunati, etc, all I can find are H-beams. Does anyone make any lower priced 5.85" I-beams, or should I just go ahead with the H-beams....assuming that I can use this piston as I hope.

 

id say get a stroker crank, a scat 9000 cast one will do the job, and they are cheap. other wise, these pistons will be sticking out of the bore by 25 thou

 

I thought the formula was 1/2 stroke + rod length + compression height to find out needed deck height? That would be (3.48/2) + 5.85 + 1.425 = 9.015". If the stock block is approx 9.025 deck height, then wouldn't that allow .010 of deck material that could be removed before the piston would be out of the hole?

Also, how strong/reliable would a Scat 9000 crank be for a 385? Wouldn't I need to keep the RPM's and power level lower for it vs a stock crank? Or what about a 5140 forged crank on strength and RPM??

 

WOULD a Scat 9000 crank be ok with a 13+ CR E85 385ci engine with good bearings, LE2 heads RPMs staying <6700, hoping for at least 430 rwhp?

 

id say yes. unless you can find an off the shelf 5.85" rod. thats a custom length. sounds expensive. but by the sounds of what you want to build, why not just do it right? forged crank and good rods to go with those pistons?

 

If the block has not been decked it could work. As you calculated the deck height with those parts =9.015".

There is no reason at this level to prefer H or I beams. Really, at any level you can find devotees of each. Both work and you are wasting your brain power figuring out which is better, because you can't.

Rich

 

Well it's not a custom length, you can get off the shelf H-beams in that length, just haven't seen any I-beams, which I was looking for because they tend to be cheaper.

As far as the block, it was a dealer replacement engine, it's a 4-bolt main block with 176k miles, have never had it out of the car, so it should still be stock deck height, correct?

So now I have to decide which setup to go with, 357 with stock crank and 5.85 H-beams, or a 385 with Scat 9000 crank and 5.7 I-beams as the cost difference for parts between the two will be nearly the same (probably <$200).
Either way, it will be an LE2 (or equivalent) headed engine with custom cam, high CR for E85, and NOT a daily or drag car but rather a weekend, autox, RR, etc only car and would like to get the most power I can out of it, while staying somewhat reliable.