Hi Folks, A few months ago I purchased a 72 Nova with a 350 supposedly bored 30 over. The engine has a tunnel ram with 2 Holley 450s' that run really rich no matter what we do. Unfortunately I do not know the crank or cam size. I think something is not matched up. I am no mechanic, but I can do most external stuff. Also, I was thinking about swapping the motor for a 383 stroker crate motor with 400+ horsepower. Any suggestions?
I miss my 72 Nova
As you already know without knowing the cu in, whats in there, who built it, and all the other important stuff, it's all a guess and will probably never be what you want unless you start over...
It happen to me last year with something I bought, motor looked amazing, ran amazing, had amazing hi end parts, but it was just to dam slow for me so I sold it. I've been kicking myself in the butt for a yr for not putting a 396 sbc in it. You can get a 396 sbc thats basically 500/500 for just a tad over 5K Brand New from Jegs. Hell I lost more than that when I sold mine
Thanks guys, yesterday we installed an Edelbrock dual plane intake with a Proform 750. The engine ran much better but still has a slight exhaust backfire when its first fired up. Even when it warms up there is a slight backfire and stall from 0-full throttle. Also, nowhere near the power of the tunnel ram, even when the TR was running crappy. The TR would fall on its face from 0-full throttle every time.
We tried rebuilding the carbs on the TR before the swap, and we still couldn't get it dialed in. New plugs, wires, etc. Maybe I should try a new distributer. The motor is 355 ci, but no idea of cam size.
You really should have an idea of the cam specs, static CR, etc before attempting to tune. My guess is that you either have a vacuum leak, very lean carb and weak pump shot, and/or improper ignition curve and initial timing.
Thanks for the response, after digging a little more I found the distributer has already been changed. The springs and weights are already gone and it has a small bolt locking the thing where the springs hook up. we used a gauge to find the vacuum on the carbs and all we could get from it was around 5lbs. we set the timing to 45 degrees. It seems to run alot better but the torque is still crappy. It wont light them up like it should, and still sluggish from 0-full throttle. I really want to buy another carb for the tunnel ram and see what happens.
45º is too much timing.You will need to varify the timing marks on the balancer.
post a video of the car,it might help.
re slugish? is that with the T.R. or new w/e you put on?
I agree with F'Bird88 on his comment pertaining to the 450 Holleys on a TR. I have them on my 327 with a TR, and I spent a lot of time tuning and changing things to get them to run well. The biggest problem they have is they are mechanical secondaries, but have no accelerator pumps on the secondaries!
If you check your engine vacuum, you might find it's low enough that the power valves are opening at idle, and you need to go much smaller to make the Holleys not run rich at idle.
After changing power valves, jets, accelerator pumps, nozzles, accelerator cams, etc., I have mine working great. But I bought two 600cfm Holley vacuum secondary carbs to use on my BBC TR engine, and simply bolted them on and they run perfect out of the box. Only change I plan for them is rejetting them to get the mix a little richer, as they run lean with my headers open at the drags.
Vinnie its swapped out to the Victor Jr intake with a pro form 750, both brand new. We fooled with the timing and we just cant seem to get it right. Maybe I should purchase a new distributer.
I use a Victor Jr intake,I dont recommend them unless you have a hot engine and like higher RPM,and or a larger engine.
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