7T9Shark

Last season, I went through the 350 by what you see below in my sig. Motor pulls very strong above 3000 RPM, but doesn't have much more punch below that number. I'm kinda disappointed. What do I need to do next to bring up the low end torque? I can't even chirp the tires. Not looking to do the nitrous thing.

Areas that I haven't touched yet are: ignition and intake manifold

73sbvert

I think the easiest way would be to bump up your timing a bit.
I think the stock static setting is around 6* or 8*, but can safely be brought up to about 12* or so without pinging (with good fuel!)

Easiest, and cheapest way I can think of...

hth

7T9Shark

Forgot to mention that I already have the timing set at 12 degrees. Maybe I should go for 14. Doesn't show any hint at pinging at 12. I thought about going the Edelbrock Performer intake route, but I think that would only help out at higher RPM.

I should also note that I have 76cc heads with flat top pistons, so I'm looking at around 9:1 C/R.


[Modified by 7T9Shark, 9:04 PM 4/24/2004]

Grinchia

You may want to do what I'm considering...swapping your cam. I bought a big block (non-original)'68 last fall with an L-88 cam on board. My compression is about 10.5:1. MEAN idle and scary power above 2500-3000 rpm, but a little sluggish below that. I plan a rebuild this winter, and am trying to decide on a cam. It will definitely be spec'd for more low-end torque though!

PatsLs1vette

id swap gears to help get you moving,3.55 or 3.70's

NHvette

:iagree: Gears get you torque - everywhere.

cardo0

I'm betting you find some torque/hp in that ignition Tshark. :yesnod: I had a friend recurve mine on his dist. machine. He said the stock MSD curve was terrible. You can start with the method under Tech Tips . Go to our tool bar above and click on tools . Go to the C3 section for Tech Tips and you'll find a tip on setting dist. advance (or something like that). Verify your getting the right timing curve.
Next place is compression. Hows about a steel shim head gasket? It's should provide 10-15 ponies just from better quench . And IMHO head gaskets (and heads) are much easier to change than cams. Its too late for the tighter chamber WP Torquer heads as your money is already spent here and your current heads are just fine for long/dependable engine life.
Intake manifolds are fairly cheap and easy to replace. You might find more torque in that new Edlebrock EPS manifold that thier bragging about with inproved mid-range torque over the regular Performer intake.
Finally I would install the 1.6 ratio rockers. This may take widening the pushrod slots in the heads but this can be done with heads on by removing the intake. BTW did you check your pushrod length? Any time you change heads or machine block deck hieght you need to do this - but an easy test. Use one of those cheap checking tools from PROFORM or MOROSO and read the simple instructions. Custom length pushrods from Summit for only $90.
The last trick only if everything else fails is a rapid leak-down lifters . And I like Crane type rather than Roads. :thumbs:
So here's my estimate is 20-30 hp in the distributor. 10 more ponies in the high ratio rockers. 10-15 ponies with tighter head gaskets. 10-15 ft-lbs with the EPS intake. And maybe 10-10 ft-lbs for those leaky lifters. All this without even changing camshafts - a big dirty job . Don't worry about headers (another long dirty job) with that short cam - stock ram exh. manifolds just fine for this set-up.
Hope this helps. cardo0

checklst

7T9Shark what runner size did you choose in the heads ?? Just a thought coming from a guy that has built HP marine engines. If your heads and cam are matched for more HP in the upper rpm range a Gear change will help your 0-60 times, others have mention timing will also help a little, but none of them will be as good as matched heads(small runner size) matching cam and intake for low RPM tire roasting toque.

Hope this helps!

redwingvette

Gear change will help. Intake will a little but not much. Torque convertor will let the motor get to its power band faster.

gr8t73

:iagree: Lower gear ratio is where it's at.

cardo0

World Produst Torquers are 170cc int. runner size which are great for a street 350". This may be larger than any stock Chevy head (about 160cc) other than the Vortec heads but much more conservative than most aftermarket heads. Now some pocket porting would help but it sounds like the ignition isn't using a good advance curve as that cam should make power down low. Adding a little more compression will help but only if the timing is corrected.
And really the timing is the cheapest and easiest to correct. Tshark just needs to do some research here and maybe find a shop with a distributor machine. :chevy cardo0

slaine

Hi, dunno what cam you have, but I had a 75 L82 vette with headers it pulled strong from 2500-6500. I put in a double roller adjustable timing chain. Advancing the cam 4deg. moved the torque down noticeably idle to 5500.
The car still reved freely to 6000. Powershifting the fourspeed was more dramatic. You're supposed to check for valve clearance when you advance a cam. The L82 had only 9-1 compression so I didn't worry about it with a stock cam.
Mike