Thread: Building 350 sbc for first time...

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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've always considered the rule of thumb to be 10:1 with iron heads. But, that cam may drain off some of yours. Just watch your timing.

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.

Originally posted by camaro_fever68
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.

Thanks for the help! This is going to be a street/some strip motor. I already have the cam on order. I wasn't thinking or I was thinking too much about the springs and whether or not the cast iron heads could hold them. The heads are not humps or vortec - they are run of the mill heads. The intake I have is a Torker II. I don't have a carb yet. To be honest with you, I was trying to follow the 540hp 383 article from AFR's website, except that I'm using a Torker II instead of a vic jr. and stock heads instead of AFRs. I guess that's not going to work is it Well I'm trying. I think it can work if I get the heads machined. What do y'all think? Or is the cost of machineing going to be the same as mediocre heads? Or do I send the cam back and get something not so aggresive?

Well with the parts budget you working on here, you not going to get no 540hp 383cid for the street. You need to go back to the drawing board with this complete set-up for mostly street and limited strip.

Send the cam back, order a XE274H from Comp. Set your motor up for no more than 10:1 CR. Zero deck the block, use a felpro 0.039" head gasket. Polish your combustion chamber smooth to eliminate hot spots. I don't know what springs you have but for the price it would take to machine the heads and put bigger springs you can get with comp and choose a bee-hive setup that is much better than standard style springs. The intake you got will work fine. Top it off with a Holley Street Avenger 770 CFM carb and some HEI ignition with msd module and coil and you have a stout street engine. You do need to try to get some better heads. Get some off ebay cheap. How much you looking to spend?

Originally posted by camaro_fever68
Well with the parts budget you working on here, you not going to get no 540hp 383cid for the street. You need to go back to the drawing board with this complete set-up for mostly street and limited strip.

Send the cam back, order a XE274H from Comp. Set your motor up for no more than 10:1 CR. Zero deck the block, use a felpro 0.039" head gasket. Polish your combustion chamber smooth to eliminate hot spots. I don't know what springs you have but for the price it would take to machine the heads and put bigger springs you can get with comp and choose a bee-hive setup that is much better than standard style springs. The intake you got will work fine. Top it off with a Holley Street Avenger 770 CFM carb and some HEI ignition with msd module and coil and you have a stout street engine. You do need to try to get some better heads. Get some off ebay cheap. How much you looking to spend?

I'll be lucky if my wife lets me spend $500 on heads! This is the article I'm talking about, under articles at top and then look down the list for the "540 hp 195 cc heads" title:
http://www.airflowresearch.com/

They say that's a pump gas 540 hp motor. That's why I was very interested in it.

Originally posted by anLS1x2
I'll be lucky if my wife lets me spend $500 on heads! This is the article I'm talking about, under articles at top and then look down the list for the "540 hp 195 cc heads" title:
http://www.airflowresearch.com/

They say that's a pump gas 540 hp motor. That's why I was very interested in it.

That parts in that engine are expensive. To reach that power goal with GM heads and flat tappet valve train and broke budget is unrealistic.

Originally posted by camaro_fever68
That parts in that engine are expensive. To reach that power goal with GM heads and flat tappet valve train and broke budget is unrealistic.

I totaly agree with you! The expensive part of the article build is the heads! If I go with the setup you mentioned above, about how much horse power am I looking at? The cam you suggested requires a 981-16 single spring, will that work with my stock heads or should I go ahead and call comp cams and try to get some behive style springs? Thanks again for all your help!