I'm running the Comp XE268 and it's pretty snarly even in a 355...right on the edge of good street driveability. I would prolly look at the 262 that Comp puts out as a bit better match, in my opinion. It would probably be much better behaved with a 305.
vortec heads?
- Thread starter ukregal
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Pace performance offers a complete kit with heads, intake, bolts and gaskets for under a grand, If you want the higher lift Z28 springs (good to .550 lift) they have those too.
with a 268 cam you're borderline on valve bind (some people say the vortecs are limited to .420 some .480) i believe you can get "higher" retainers and you'll be fine but i would highly recommend the machine work on the guides and the proper springs. the last thing you want is float or bind. you probably want the 981 springs with 400lb seat pressure. i was talking with one of the guys on this forum and he had alot of problems with the lesser pressure springs (for some reason Comp cams gave him the wrong number). also, RUN GOOD OIL!!!!!! with the XE series flat tappets this can not be stressed enough. valvoline makes the VR-1 oil that has alot of ZDDP--critical for break in, also use cam break in lube.
good luck with the engine, and remember drive it like you stole it! 😀
good luck with the engine, and remember drive it like you stole it! 😀
Well, vortec heads can indeed run .480" lift cams, because, well, the XE268 I'm running now is exactly that. It works slick. I dunno if there's a diference with the 305 and 350 vortec heads.
But, as stated, get the cam-matched springs from Comp... the stock springs can't handle the extra lift and you'll get valve float and/or bind pretty damn quick.
But, as stated, get the cam-matched springs from Comp... the stock springs can't handle the extra lift and you'll get valve float and/or bind pretty damn quick.
heads
guys know ur sh*t before misleading someone into f***** their sh*t up!
i had a set of 305 heads. i can tell you that they had about a 56cc combustion chamber so do the math on that with a 305 piston. that was stock with a dished factory piston too so depending on the psitons you use(hopefully a raised dome) with the 64cc or 76cc heads you should check out ur compresion ratio. also, the 305 vortec head has 1.84 intake valves 🙁
guys know ur sh*t before misleading someone into f***** their sh*t up!
i had a set of 305 heads. i can tell you that they had about a 56cc combustion chamber so do the math on that with a 305 piston. that was stock with a dished factory piston too so depending on the psitons you use(hopefully a raised dome) with the 64cc or 76cc heads you should check out ur compresion ratio. also, the 305 vortec head has 1.84 intake valves 🙁
did you read the entire thread? we said to check what size chamber the stock heads have vs the vortecs. the compresion numbers i gave are based off of a 8:1 base ratio--stock on most gm v8's.
and are your 305 heads with 56cc chambers vortecs or standard?
also he asked if he can use stock pistons--he's not rebuilding the engine just doing some mods to increase power.
i meant the stock springs. sorry.
and are your 305 heads with 56cc chambers vortecs or standard?
also he asked if he can use stock pistons--he's not rebuilding the engine just doing some mods to increase power.
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i meant the stock springs. sorry.
the last time GM put a dome piston in an engine it was the real LT1 1970
nothing else
so dont worry go ahead buy these heads and do what i said previously and enjoy yourself !
nothing else
so dont worry go ahead buy these heads and do what i said previously and enjoy yourself !
If you want high compression, the most efficient setup is a flat top with a small chamber head and a tight quench area. This allows for a more even propagation of the flame front across the piston dome than a domed piston does for more complete combustion.
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