hi all,,,I recently changed my intake and carb on my 305...I put on the performer rpm and a holley 750 vac. sec.(I know the 750 is alot but it was free,and I think Ive got'er tuned in pretty good)my problem is that it feels like ivelost most of my torque.I have also put in a new hei vac.advance distributor. The throttle response is great so i dont think its the big carb.Its just no more tire smokin burnouts since the changover.Could it be that i have messed up the power range with still having a stock cam? A cam change(considering the 270H i think it is)and hedman hedders,Y-pipe,and catback are coming in the next few weeks. Will this cure the no torque prob. or is something else out of whack?ive got it timed pretty close(by ear of course,The timing light is just about useless!!!)But with a dialback style light I am getting 36 degrees
total advance @2800 rpm...any help would be great. thanks in advance

 

give it more timing..

lights are accurate to a point but the engine knows what's best..

take it out for a spin, keep advancing the timing until it pings and then back it off just a touch..

after that i would say maybe the distributor has the wrong advance curve? something to that effect..

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Webmaster: www.IROC-Z.org

 

what kind of vacuum reading do you get at idle?

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FloridaRacer.com

 

it hops around from 13 to like 15,,,,I also suspect a possible intake gasket leak,,,i found a small puddle of oil by the front drivers side bolt,,but maybe thats just a valve cover gasket

 

I also forgot to add that between 3000 and 5000 rpms it feels like its got a ton of power.. just from idle(1200) to 3000 it feels like my s-10

 

Gotta ask: Are you disconnecting the vacuum advance when you check the total timing? If not, do it, then check.

At 3000, you're getting good into the range of the intake manifold. At 5000, the stock cam is done. That combo will make for a very narrow powerband.

Changing the cam will help, but may not recover all of the low-end torque. That's why they make higher stall torque convertors.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

I agree with 5.7. You will lose some low end TQ with a bigger intake manifold, but the gaines about 3000rpms are well worth it. A new cam is the only way to regain some low end TQ, but I would shoot for something that takes advantage of the 6500 upper limit of the RPM intake. Heads would help too, but you have to decide where you want to make your power.

A higher stall converter (like 2800-3000) will help you spool up faster through the lack of low end TQ (and I'll bet you still have plenty).

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

Sounds like you have a vacuum leak,You should see upwards of 18-20 inches with a stock cam. That is alot of induction for a mild 305. you will lose some lowend. Until you find out the reason for the low vacuum you wont be able to tune it IMO.

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

 

Yes,,I have disconnected the vac adv.,,And also I have a 5 speed tranny...I have suspected a vacuum leak,,could that kill the torque? I knew i shouldnt have used the gasket that came with the intake(edelbrock?)
any suggestions on a good cam for my motor?
im going to put on the hedders and catback the same time i do the cam.also why would my
vacuum fluctuate so much?vacuum leak? I have
crane roller tip rockers also.(1.6 ratio)
you have provided much help,,thanks much,anymore would be appreciated too