what is the biggest lift you can go with on a 305 or 350, I heard about .470 is about as big is you want to go and was wondering if the valve springs would bind or any other interference problems would occur. BTW, does anybody know the aprox specs on a factory cam. thanks

 

Yes, the stock springs are ok to about .470" lift. But, if you don't match your new cam with the proper springs, you can have some pretty bad valve train geometry. The valve will bounce on and off of the seat at valve closing. Even if you go with a cam that is within stock spring limits, your old springs are worn out and your valves are all gummy.

IMO, if you are going to dismantle an engine to install a new cam, you might as well fix and replace and clean up as much as you can. Go ahead and get new springs, retainers, valve seals, and have your valves cleaned off.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End with 2.77:1 Gears.

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Catco 3" High-Flow Catalytic Converter, Hooker 3" Aerochamber Cat-Back System, Transgo Shift Kit, Performance Resource Chip, Accel Ignition, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET: 14.32 @ 97.7mph
(corrected for elevation)

 

listen to mr. miagi daniel son..unress ru on budgret and dont mrind weaky spring....
confucious say ... if ru need geometry in school...run drefintry need it in TPI motor
i also say blue bottle cover up weak springs

 

I was wondering because I recently built a .060 over 350. everything is pretty much stock but I had a brand new 305 rebuild that spun a rod bearing and it had a really(to much) agressive cam so I took the newly rebuilt stock 305 heads and new cam and figured I would try them on the 350 for a little taste of a higher comp motor but the extra cubes tamed the cam a little too much and was thinking of replacing it with a little beefier cam (2000-5500) rpm range. what do you guys think?
ps: 87 firebird, 5 speed, bw 9bolt posi from 89 275/50 r15 on the back

 

oh yeah, Q-jet carb and HEI with headers and 3" single exaust and found a dual snorkel air cleaner. right now I have 18 in/hg intake vaccum and it idles fairly smooth