That is exactly what we are trying to determine.

 

For what it's worth I'm pretty happy with a custom cam I had ground for my 385. I'm still doing some tuning on it and have not pullied up yet and so am at 5psi boost. The grind I used is 228/236 510/525 113lsa +2. This has a nice lopy idle and will make power to 7000 rpm and beyond. I ran my combo on a desktop dyno figuring 8psi and came up with 680fwhp. Right now I'm at about 540 rwhp so the numbers should be close to what I figured before building it. I also looked on the board here at everybody using similar cams for blown applications, but in the end went with what my engine buider recomended when doing the shortblock.

 

its a very similar cam to the ones we are discussing... maybe too much overlap... I am going with a 116 lsa this time... same duration more lift.

 

with good springs what is the highest lift you can run on a stock lt1 bottom end just wondering cause i am new to the lt1 im an old pontiac man

 

I'm not sure why the bottom-end would matter.

Max lift is more a function of valvespring choice, set-up height, retainer/valve seal clearance, and lifter type.

I don't generally recommend over .600" with a hydraulic cam because the open spring pressures get over 400 lb which could compress the lifter at low rpm and shorten their lives. You have to carefully set up the valvetrain to reach .600".

With a solid roller, the sky's the limit. How long [or short] do you want your springs to live? It seems like .650" - .670" can be made reasonably reliable.

Mike

 

I think he is asking Piston to valve wise....I think the answer still right around .600 with out pulling the head and claying it....

 

Piston-to-valve clearance is dependant on duration, LSA, and advance, NOT max lift.

Mike

 

hey mike what might those be

 

Duration, as in intake and exhaust duration of the cam: more duration means less clearance.

LSA as in lobe separation angle: smaller LSA's mean less clearance.

Advance as in cam advance: generally higher numbers (positive or negative) will have less clearance.

Mike

 

I might add that Bret did choose the 12º exhaust duration over the intake on my cam?