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Author Topic:   My Pontiac
Pit Bull
Dirt Full Roller

Total posts: 42
posted May 21, 2001 05:57 PM
My pontiac 400 has no power. It has the big 500 cfm 2 barrel carburetor on it, with a large 4 barrel intake with egr blocked off. Im running open pipes, and cant afford to tear it down and build it up like it needs to be built. Would a 4 barrel carburetor really make that much of a difference? Im seeking power wherever I can find it. Please help!

Pickel
Dirt Freak

Total posts: 239
posted May 21, 2001 09:33 PM UIN: 25419780
Back when I ran the Pontiac 400 I set the rockers like you do a solid cam. I ran a hydrolic but when I set them like the solid it ran wonders. Another way you can set them to get more power out of them is with a compression guage. Take one cylinder at a time and start tightening the rockers one at a time until you get maximum compression. It's time consuming but it's well worth it. You also need Chev. lock nuts for the rockers to do this.

widebody
Dirt Full Roller

Total posts: 74
posted May 22, 2001 07:29 AM
check the simple things like fuel pump, firing order, timing. Timing on a pontiac should never go past 36. more like 34-35. The rotation is reverse on the dist from chev. If some one helps you who isnt familure with Pontiac they can adjust the power right out of it in a hurry. So double check your firing order(been there)
Like Pickel said play with the valves a bit. I run my hyd cam real loose. it ll clatter a bit at idle. Adjust them a cylinder at a time also.

What jet sizes do you run on your 2jet?
What cam do you run? What gear do you run and at what RPM?
Pull your plugs that'll tell you all you need to know..

Pit Bull
Dirt Full Roller

Total posts: 42
posted May 22, 2001 12:01 PM
I am currently running 60 size holley jets with the 2 barrel I have. Should I go a bit bigger? I had 70s in it and it bogged out off the corner. Suggestions?

racer17j
Dirt Maniac

Total posts: 165
posted May 23, 2001 02:26 AM UIN: 54865418
onr thing i found to help my 400 was to keep it as cool as posible we ran a 3 core radiator and alway got slower toward the end of the fearture till one night we got a hole in it and borrowed a 4 core from a buddy and never had the problem again it ran about 220 before and got it down to 205 helped alot. it was a bone stock carb and all never did anything else to it but changesd to a hotter plug

Pit Bull
Dirt Full Roller

Total posts: 42
posted May 23, 2001 09:18 AM
The radiator in it now is an aluminum single row radiator out of a chevy pickup. The row is about an inch wide. It has an 18 inch fan, with a good shroud, and never gets above 190 degrees. I have done no modifications to this motor - i just had it laying around and decided to drop it in. I did some figuring, and it has a compression ratio of 7.6 to 1. No wonder it has no power! I think a swap to a lower cc head is in order to get some horsies!

widebody
Dirt Full Roller

Total posts: 74
posted May 23, 2001 11:40 AM
the last stock 400 I ran I still had 71 jets in it it was a tad rich but, i left it alone. the plugs were stock heat range. and a 36 degrees advanced. What kind of RPMS are you running? A stock engine wont pull past 4500, itll flatten right out and wont rev any more. try a higher gear if you run in second or third. I ran my stocker in 4th with 3.70 gears on a half mile track. it pulled fine. And like 17 said keep it cool.
Check your timing and plugs. One last thing I can think of is make sure your timing is correct. They changed timing marks on the balancer alot. double check 0 and use a light with advance/retard feature. than mark the crank.

Good luck, Widebody

Pit Bull
Dirt Full Roller

Total posts: 42
posted May 25, 2001 08:41 PM
Im running in 2nd gear with 2.73 rear gear, so im not revving it very high. It has most of its power down low. Im probably coming close to 4500 on half mile tracks at the end of the straight away. Im going to check my timing tomorrow, and set it right at 36 degrees. Ive already found true TDC on the balancer with a piston stop. Thanks for all your help guys! I really appreciate it!

Pit Bull
Dirt Full Roller

Total posts: 42
posted May 27, 2001 02:33 PM
I found a problem! When I set my timing, I found out that it was set at around 44 degrees total advance rather than 36 as it should be! The thing that surprises me is that it didnt ping, diesel, or do anything of the sort when it was all the way up at 44 degrees. Hopefully getting it back down where it needs to be will give me a few ponies.

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