Finishing out my combo, overcammed i do believe [Archive] - Chevelle Tech

: Finishing out my combo, overcammed i do believe


RussD
Jan 31st, 04, 5:52 PM
Alright guys, looking to possibly wake up my combo a bit, probably to do more down the line, would like some critiques/suggestions.

Motor as it sits:
357 cu inch
350- .040" over SpeedPro flattops, 4 valve reliefs(I assume 2cc's per relief)
Ended up not zero decking the block, but the deck has been shaved a little bit.
RPM airgap intake
750 cfm vac secs Holley(3310)
RPM aluminum heads, 64 cc chambers head gaskets are the E-brock recommended Fel Pros believe the compressed thickness is .039"?
Cam is 302 adv duration 240ish at .050" .509" lift on Intake and Exhaust Hydro. 108 lobe sep. (One of the older grind SSI cams that PAW sells)
I believe compression is right around 10-10.5:1

When I did the motor I got in a snag for money and had to sell my Continental 3k stall. So its a stock converter with a TH-350 trans

Rear is a 3.36 pegleg 10 bolt.

Though I know this combo is badly mismatched as it sits, the car does run very well, I just know there's more in it, and as I approach graduation from college I'm lookin to tinker with some things.

Would say a 3k stall with 3.73 posi- 4.10 posi be more of a matching combo to the motor thats in there? Would I still need to recam?

When I was building the motor, I had picked up that cam(engine builder recommendation old school racer"gasser" building type) along with the Ultradyne that a number of you guys suggested, the 276/286H12 lift is an even .454" on that cam intake and exhaust. The guy really liked the other cam better as he knew I liked the aggresive sounding lope and whatnot so thats what he stuck in.
edit- I should note, at the time my motor was being built, I had a line on a 4.10 posi rear that I was going to pick up, and I still had the conti 3k stall, so the engine builder wasn't really planning around a 3.36 pegleg and a stock converter.

I just know this combo has something more in it, just looking for a lil more pep I guess. Just kind of curious if I should up the stall and the rear gear, or if its definately a re-cam situation.

Ultimately I'm just looking for an aggresive sounding quick street car. I rarely go to the strip anymore.

Any more input needed, just ask, and thanks in advance for any replies!

BIGMOE65
Jan 31st, 04, 6:10 PM
I had a stock convertor with 2.73 rear gears and a comp cam 270H, it has 270 advertised duration, 224 @.050. It was a slug off the line. I replaced it with a 2200 stall convertor and it feels like a whole new car. If I changed the rear gears it would be even better but I like the 2.73's on the freeway. I would just get a convertor for now. By the way the swaybar I got from you is working great.

Racerdoc
Jan 31st, 04, 6:16 PM
3 things:
1.you need around a 3500 stall with that cam. With the qaulity of converters floating around these days it shouldnt be too bad.
2.you need at least a 3.90 (preferably a 4.10) gear.
3.run alot of initial timing. I run 24 degrees of initial timing. Your cam has alot of overlap so you should be ok.
Doc

Wolfplace
Jan 31st, 04, 6:31 PM
On the engine:
Need to know what piston you used.
If it's the good Fed Mog 1.560 or the rebuilder 1.540 c/h
Assuming your deck is cut .005 to about 9.020 you are pretty low on compression for that cam.
A pretty close guess would be 9.7 with the 1.560 piston & 9.3 with the other.
As it's done I would put a felPro 1094 gasket on it. This alone will raise your compression to
10.3 or 9.8 depending on piston & should improve the quench.
And yes,,these gaskets will work excellent with aluminium heads
Even with this those SSI cams have pretty slow ramps & at 240 it's to big but this will help a bit ;)
Also, if it isn't already advance the cam about 6 degrees.
=====edit==
Forgot to add,, all this is still bandaiding too much cam, my choice would be the above mentioned Harold/Lunati on a 108 lob sep.

RussD
Jan 31st, 04, 6:56 PM
Thanks for the input thus far!

Mike, Pistons are from summit, part#TRW-L2256F30 but the .040" over version probably TRW-L2256F40?

Forgot to mention, the cam in the motor is installed on a 106 ICL(I dunno how much advance is ground into the SSI's?)

I looked up the current gaskets, they are the Fel Pro 1003 with a Thickness of .041" compressed

Also, even with upping the rear gear and converter I would be better off with the other cam on a tighter lobe sep? Guess if I ordered that cam then I'd end up with 2 cams in my bedroom and 1 in the car, still have the H12 sitting brand new in the corner...
If I were to go with the cam like I have but the tighter sep. for the aggressiveness what would be the ideal stall and rear gear?

Wolfplace
Jan 31st, 04, 8:08 PM
If you installed it at 106 ICL it's 2 degrees advanced.
Didn't realize you already have the H12,, I'd run it. It is a bit mild but an excellent cam & I think it's a ton better than what you have.
Unless of course you can sell it & get one on a 108 :D
The 108 should make more power & be a bunch lumpier, the 112 will be pretty "civilized"
Those pistons are 1.560's as I recall.
I would still change the gaskets if the pistons are in the hole .015-.020 which is where they should be assuming only .005-.010 is cut from your block.
====edit=======
If you are going to get another cam I would probably bump it to a 280/288H8 if you get the compression up
Post a question to Harold if he doesn't happen to see this one & see what he thinks,, he be the man ;)

RussD
Jan 31st, 04, 8:58 PM
Mike,
Thanks for takin the time to help me out. So with the pistons that are in there, with the other FelPros you recommended I should be up to about 10.3:1, correct? Then if I were to go to the 280/288h8, what should I be looking to run for optimal stall and rear gear?(assuming just the gasket change will give me enough compression for the 280/288h8)
I really do like the sound characteristics of the cam thats in the car, although I already have the H12, I really would rather just buy another cam on a tighter seperation. Tried selling it a bunch of times, wouldnt go for even 100 bucks and I got ~$190 with shipping and tax and all that jazz, Ive just written the box off as a 190 dollar hockey trophy stand in my closet, lol
Thanks Again!

Wolfplace
Feb 1st, 04, 12:52 AM
Assuming the blocks is cut to 9.015-020 yes you should be 10.3-10.5 & that is plenty for that cam, possibly more depending on what your goals are.
If I were doing it I would be considering both the 280/288 & 288/296 but again I would consult Harold as you are probably tired of buying cams to "test" :D
Lotta folks on here more qualified to give you convertor/ gear advice than I. ;)
Been a while since I have done anything but engines except for some test driving now & then & when I drove if it didn't have a clutch I didn't feel like I was earnin my keep,, never could figure out what to do with my other foot :D
Drove a friends Anglia a while back with a transbrake & told him he needed to put that stupid button under a "clutch pedal" so I'd know what to do with it :D

Scott_68_SS
Feb 1st, 04, 2:25 PM
Russ, I'd be interested in a UD cam at a discount.
I'm going your way sort've (Irvine) on the week of the 16th. mail me.

Wolfplace
Feb 1st, 04, 10:16 PM
Originally posted by Scott_68_SS:
Russ, I'd be interested in a UD cam at a discount.
I'm going your way sort've (Irvine) on the week of the 16th. mail me. =

Hey Russ,
There ya go,, part payment on your new cam of choice & one less "Hockey trophy" ;)

Scott_68_SS
Feb 2nd, 04, 2:56 AM
Well, maybe just a different closet. :D It's for my old 350 motor. If gas keeps going up, I'll want a mileage motor.