Holley 390 CFM on 225 / 6

[Jeff Lemon]

I have a 225 with clifford manifold, headers, 2 1/2 inch exhaust and Johnny Dart Dist. Cam and Head are stock. Starts good but when starting out wants to stumble or hesitate. Do I need to rejet the Carb or what. Engine is a 1965 in a Valiant 200.

Thanks, Jeff

 

[Bad Sport]

First thing I would check is pump shot.

With the engine not running, look down in the bore and crack the throttle with your hand and see if you get an "instant" shot of gas. It should happen immediately, if you get some movement and then see the shot that could be your issue.

 

[jbc426]

First thing I would check is pump shot.

With the engine not running, look down in the bore and crack the throttle with your hand and see if you get an "instant" shot of gas. It should happen immediately, if you get some movement and then see the shot that could be your issue.

First thing! Check the pump shot and the overall condition of the carb. Then insulate the carb from the intake heat using two of the thick carb to manifold gaskets and a large piece of aluminum to reflect and dissipate the heat like the heat shields they sell.
The next HUGE thing is timing. My Super sixed, Dutra dualed exhaust, .60" cut head with bigger valves and a Doug Dutra spec'd Erson cam. It was the small one too.

With the vacuum advance unplugged, the initial timing was set at 22 degrees before TDC. I welded up the advance slots in the distributor and filed them back with a chain saw sharpening file until I got 32 total degrees timing. Then I hooked the vacuum advance to the Manifold vacuum. This brought me up another 8 to 12 degrees advance at idle, but I forget the exact number.

This transformed my motor from a slanty that could barely burn rubber with 3.23 using a brake stand, to a car that could smoke the tires. It felt like it gained 70 hp on the bottom end and the mid-range. It was was awesome!

Everyone told me it should n't and can't run with the timing lki this, but it loved it. I wa sunning the Holley 350cfm universal carb. Here's some pics before the aluminum plate was put on under the Holley, but you can see it under the carb o the last picture. It really made a difference on hot start.That is before I discovered the timing curve it likes.