Stock 193 springs are described as
VALVE SPRING PART NUMBER IS 3911068 (SAME SPRING USED WITH THE OLD 300H.P 350 CRATE)
INSTALLED HEIGHT 1.70" PRESSURE @ INSTALLED HEIGHT IS 80 LBS * PRESSURE WITH VALVE OPEN IS 267 LBS.
THESE SPRINGS ARE GOOD FOR .550" LIFT BUT CLEARENCE BETWEEN GUIDE AND RETAINER MUST BE DOUBLE CHECKED BEFORE ATTEMPTING.

BUT how far can the stock 193 heads be taken without running into clearance issues with valve to piston and the push road oil ring? My cam is just a bit more aggressive than the stock one, And I'm thinkin about 1.6 ratio rockers to get a little more lift. DD2000 says I should get about 10hp out of this upgrade, but I'm worried about how far I can take it. Can I get upto 0.50?

Cam as advertised with 1.5 rockers
Intake: Advertised 262, @0.50 204, lift 0.42
Exhaust: Advertised 272, @0.50 214, lift 0.443
Cam with 1.6 rockers
Intake: Advertised 262, @0.50 204, lift 0.462
Exhaust: Advertised 272, @0.50 214, lift 0.488

Think it'll work?

 

[QUOTE=Tony78_280z]

Cam as advertised with 1.5 rockers
Intake: Advertised 262, @0.50 204, lift 0.42
Exhaust: Advertised 272, @0.50 214, lift 0.443
Cam with 1.6 rockers
Intake: Advertised 262, @0.50 204, lift 0.462
Exhaust: Advertised 272, @0.50 214, lift 0.488

Not too sure, but I think your calculations for lift are off. I come out with .448 & .472 for lifts, not .462 & .488

 

Yes that will "work", in the broadest sense of the word.

Whether it will actually accomplish anything, is a whole different matter. That all depends on whether the limit to the port flow is the valve opening, or the swirl port ramp.

The potential clearance probelms aren't the valves to pistons, or any of that. It's the bottom of the retainers running into the top of the valve guides. But I don't think that will be a problem.

BTW Zeder's lift calculations are much closer to correct than the original ones.

Summit 1102 cam

 

Correct my math if wrong, but the differene between 1.5 and 1.6 is .1, or a tenth. Multiply the lift numbers by a tenth and you get my numbers.
0.420 * 1.1 = 0.460
0.443 * 1.1 = 0.488
AM I missing something?

 

whoa, you didn't do so well in math eh?

take normal lift, and divide by 1.5, then multiply by 1.6. Or take your original lift and multiply by 1.066666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666

zed'r is right


if you've got it all there at home, then bolt it all up, rotate the engine over and use a caliper or feeler gauge to check clearance between your positive valve seals and retainer. If you don't have it all at home, then get a real cam and heads

 

Evidently....

The correct procedure is:

Divide given lift by stock ratio (1.5), multipy result by new ratio (1.6).

Or, if you have a cam where you have the lobe lift numbers, they would be multiplied by 1.5 for the "stock" valve lift, or 1.6 for the "increased" lift.

 

Well, with those numbers, it doesn't seem to be very effective. Prolly closer to 4-5hp gain. Not worth the time or money.

Thanks for correcting my math for me.

Yeah I plan to get Better heads some day, but these were in excelent condition, and I needed to get the car running. I did spend a little time porting and deshrouding, but I didn't waste much money on them. Don't sell them too short as they'll burn the tires and launch me threw the stop light with a quickness! As for their top end, I haven't noticed them peter out on me too soon. I'm sure I'll go for the vortec kit from SDPC one day. I got rear suspension, and alot of body work to do before I even look at my engine again.