Original Message
390GT Mustang question
By Mike - 05/15/2003 10:46:32 PM; IP 24.197.167.80
Hi all,
I've owned 3 '67/68 390GT Mustangs. I'm on my 3rd now. This '67 Gt 4spd 390 Fastback just doesn't seem as peppy as the others. Maybe it is b/c it is totally stock but I think there is more of a carb. issue.
The orig. 4150 Holley was rebuilt about 2 months ago just b4 I got the car from Pony Carbs.
The car makes good power about 25mph and when the secondaries kick in. It seems to be lacking punch off idle and down low. If I mash the gas from about 5mph the car just seems to wind out slowly until the secondaries open. I can even seem to break the tires look in 1st gear from a stop!
I think the car has a posi 3.00 rear in it but that should make the difference.
My mechanic recently did some work on it and he said the plugs were 2 heat ranges too low and fouled b/c the car was running too rich. He said he also turned the idle mixture screws all the way in get it running best and when he did that the car didn't stall.
Right now the timing is set about 14BTC at idle and the vacuum port at idle off the carb, pass. side tip of the metering block is pulling about 6lbs of vac.

Any thoughts would be great,
I wish I had another similar carb. to slap on to compare.
The PO said the motor has 5K on it and the compression is 170 across the board.

Mike
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390GT Mustang question -- Mike, 05/15/2003
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