Another opinion question
BJR, we differ on opinions for the heads, which is no big deal. I agree that factory parts could be used, but the 4" arm isnt a factory part. The stock caps can take 600hp without moving, but not witha 4" stroke. At that point, the cheap crank is flexing a lot, and the mains will move. a N/A 340 will make 600hp easy, but not at 5500rpm like the 4" crank will. added stress means better stuff..just the way it needs to be, to stay in good shape. The pistons speeds with the 4" arm are much higher than a 3.31, and a bit higher than a 3.58. Hyper pistons are at their limit with the 360 at 7K rpm. The forged pistons are needed for the 4" to be safe at 6500 on a regular basis. H beams in decent form (meaning better materials, but not as good finish machining) are $300 a set. It cost me $70 for ARP bolts, plus the resizing for 150, plus narrowing the top end for some pistons to fit. And that gives me a 30-40 year old casting, that is no stronger except for the bolts. For under $100 more, I can have longevity, and peice of mind the factory rod cant give. It make sense to spend it."back in the day" MP had quality parts..that was a long time ago, and for the most part, the old V8s parts are either not available, way overpriced because of MP's dealer pricing structure, or just plain "not available, see us in 3 months.." I had accounts at several dealerships for parts..but having valve springs that loose tension in one season (up here thats 4-5 months), leaf springs that sag 3" (not settling..sagging)after 5 mths, and cams that need 8* of keyway just to get to where MP recommends is not a quality part. Mega blocks that sonic check to be .020 thick if you bore to the max 4.5", and are like trying to find a needle in a haystack because they cant find a decent foundry.. It's now easier to buy a used big block crate motor, and use only the block for a buildup. Sorry for the MP rant, but I'll take the aftermarket stuff, and the assumed "fixing" until MP gets back to supporting us with decent parts. So, there are cheaper alternatives..there always are. Just a question of how you feel about things really.