# carb /exhaust question.



## Lithium (Apr 23, 2009)

Right now my 68 has a 400 with hi rise edelbrock manifold and a 650 edelbrock carb with hooker headers and 2 inch exhaust with cherry bombs.

The engine is fighting to breath and I want to upgrade some things.

I am thinking of installing a 750 edel carb or possibly an 850 not sure whats best for my engine. Next Im probably gonna go with the flow master either 40 or 44 and if I do that what size exhaust should I be running 2.5 or 3.

My engine is running around 525 horse right now.

My last question is anyone have any good suggestions on traction bars due to wheel hop and I want to switch to some kind of posi rear end but nervous about snapping stuff. Should I go with full posi or a limited slip.


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## auburnconsulting (Nov 3, 2008)

yes posi is a must. dts on grosebeck in warren michigan can do the rear correctly. caltrac makes good products. 525 hp with a 650cfm? a 400 should use a 750. 2.5 dual is plenty for a 525 hp engine


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## geeteeohguy (Feb 2, 2008)

"525 HP with a 650 cfm?" My thoughts exactly. Go with at least a 750 carb. I used Lakewood traction bars on my '66 with good results. They're adjustable, have heim joints, and don't ruin the ride quality. They DID bend a bit at the brackets after a few years. Easily fixed.


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## Lithium (Apr 23, 2009)

Thank you gents appreciate it trying to race to get stuff done before summer gets here.

Between my last two posts I have plenty of work ahead of me and appreciate you all responding so fast.


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## Rukee (Feb 8, 2007)

I don't think you're running over 500HP with 2" and a 650. Larger on both ends will help a bit.
I would do an Auburn limited slip carrier unit and convert your open rear end to a limited slip.


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## jetstang (Nov 5, 2008)

If you dyno'd at 525 now with a 600 edelbrock, and small exhaust, you should be well over 600 HP with a 750, if you went double pump, maybe 625. At that HP level, a posi should be required.
Most 400 Pontiacs are up to 350 HP with a 600 carb, good cam and compression, torque is another matter. Bench racing numbers don't translate well to real HP. What is your combo that is building this power? What stall and gears are you running, and how do you get a single spin to hook?


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## Lithium (Apr 23, 2009)

Sorry took me so long to respond on the HP. I picked the car up from the painter approx two months ago to get some other work done on it and the mechanic that did all the engine work told me that was the HP out put as of then.

As of today I still do not have a list of what heads,cam etc he put into the engine I only know the cosmetics from looking at the outside.

I purchased the car from my brother for the price he had into the engine alone as he was hurting for cash and I got a steal more or less.

I have been busy up until last week and now am scrambling to find all this info out myself and get the car road worthy.

I have drove the car three times as of yesterday and I cannot hardly push the pedal without the tire breaking loose, I also tried the his/hers out and when I caught 2nd the car about went sideways and when I drive down the road steadily increasing speed the 4 brrl is not kicking in until im doing 70-80 mph.

I have yet to make sure the speedometer is working properly but I do know its within 10mph due to traffic flow.

Not sure what gears are in the rear end yet but I do know when im between 55-65 the car is not even near winding out.

Sorry I dont have more specifics for you all as I can only tell you what I have seen and been told up to this point but I will fill you in as soon as I know.


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