Originally posted by anLS1x2
I'm making this motor into a 383 stroker. I am using stock cast iron 64cc heads. My question is, Can I use a stiff spring on these heads? The cam I've ordered is a Comp Cam Magnum 294-S with a .525 lift. Will the stock heads support a lift of this size? Can I machine the heads to work? Also, I think my compression ratio is going to be a bit on the high side and I want to run pump gas. The pistons I have are 383 Speed Pro forged aluminum part #L2491F30. With the 64cc chambers I beleive it's 10.5:1, is that too high for pump gas? I am learning here so any help is much appreciated!

I think the 383cid is a great idea. There is no substitute for cubic inches. Bet you never heard that one before. lol ...It stands true though. What heads are you using? I'm taking it as either camel humps-461-462-186-291-492 or vortec. Any stock head that didn't come or already has screw in studs and guide-plates needs to be machined and and the spring pocket will need machining also. Comp has some springs you might could try to talk to one of the reps about like conicle springs and bee-hive springs that might could work for your app, but you still need screw in studs because you'll pull the press fit out with that much cam. Is this going to be a strip/ some street motor or a street motor. If street you need to think about all that cam and compression. 9.5 is a border line. There are little things that will help keep you out of detonation such as has your block machined for a zero deck height and run a .037-.039 quench area. Then fine polish your combustion chamber to help eliminate hot spots.
If you already have the cam it may bleed enough low rpm pressure but ef you don't and you want that big of cam order it with a 106 lobe separation angle for 383, 108 for 350, and 104 for a 400. A victor Jr. and a 750 double pumper would make it a screamer, but only for strip/Pro-street. Also 1.6 rocker on the intake and 1.5 on the exhaust side.