I am rebuilding my 355ci small block which was a dog on the low end primarily because of big crower solid cam #00355 - 244/250 .503/.518 - 106 int c/l - to put into my camaro below -

so far I have added :-

H618cp hyperteutics - 0.125" dome tops (replace PAW cast knockoffs - TRW 2304 .100 dome pistons)

milled sportsman II's 64cc by .018" (hope thats right - .006" per 1cc formula - to 61cc's guess)

I also wanted to use a .015 head gasket

The above was intended to raise compression so that I could make better use of the big cam

However I have changed plans to try and build around a big cam - so my idea now is to abandon the big solid cam and Victor Jr. which was on the engine

putting in a generic brand hydraulic from PAW 214/224 - .443/.465 - 114 or 112 int c/l and a torker II from my current engine or my performer from my previous 305 setup

and use the gasket from the Summit rebuild engine gasket set - what do you think?


I intend to use more torque with my 4.11 gears and use 28in. slicks to keep the engine in the band of that cam - 1500 - 5500 rpm - to get my 85 to run better strip times without NOS (its a formula from "HOW TO RUN 11 SEC IN A THIRD GEN. publication - although the writer used a 406 instead - I know there is a big difference)

Best I did with big cam/Victor Jr and slicks with the Edelbrock 1406 carb was 14.2 - and 13.875 with 850 holley - when I added NOS 150hp system, the car did 12.8

what do you think about my new approach - thoughts on the intake and cam welcome - any gains to opting for the current 218/218 - .454/.454 in my current combo below (buying a different cam is not an option right now!!)

or should I go back to the big cam now that I MAY have stepped up on the compression (perhaps add .015 shim gasket) and see how that cam responds now??

Thanks for your help and advice in advance

Trevor

 

I think you're on the right track for going slower.

What tranny are you running? A higher stall torque converter should be all the cam needs to do its work.

 

My thoughts exactly. You went from a cam that is on the big side for your motor and went to a cam that is too small for the motor. I am curious what compression ratio you were running with that big solid crower cam and victor jr. Anything less than 10:1 would be way too low, probably even 10.5:1 or 11:1 would be closer to what you would have needed with that big cam. Also as five7kid mentioned, with that big cam and slicks you should be running a 3000 or 3500 converter. If you want my honest opinion, step the cam down, but not as drastically as you were thinking. Unless you plan on shifting around 6800-7k rpm, go with a cam with specs similar to these:
230/235 @.050, somewhere around .480/.510 lift w/ 1.5 rockers and a lobe separation of 110* or preferably less. This will give you good top end but still keep some torque downlow. Its realistic to think you could and should be in the 12's all motor and the 11's on the spray.

Seth

 

If you are spraying you may want to keep a wider lobe separation, I forgot about that. 110 would be as low as I would go for LSA if you still plan on spraying.

 

My engine in the sig w/ new time at bottom needs tuning as we got rained out after 2 passes, but I did'nt think 13.09 in a 3440lb car w/ 3.42 is too bad.

 

Not bad at all. If you were running a split pattern cam and a little more compression I bet you would go quite a bit faster...

 

That's kinda what we thought for the motor itself being a no frills mill-just a mild cam's about it, I'm gonna tune it and hopefully get 1 high 12 pass on it, then I'm done for the season with the motor till winter when I can build the real deal. She's deadly consistent so that's one plus of having a small motor

 

This is what I would do in order to make the motor more efficient:

Cam - hydraulic roller 220/230 114 to 116 degree lobe sep (nos)

Perfromer RPM intake manifold

2400-2800rpm converter

Step down the rear gears to run 3.73 with 28" tires


What this is going to do is add more torque (so you will need less converter) while pumping up hp at a lower rpm (lower gears). When you spray the motor it is gonna need to still pass the traps at the same rpm as the motor only would require - so you go with lower gears. 10:1 compression is probably the best compromise to have.