looses power

[Frank Castros]

GT/HA '66 Plymouth Belvedere, 426 Street Wedge, 3,675 lbs.
2.77 first gear ratio, 4.89 rear gear, shifting @ 6,500 rpm, 7,500 rpm at the finish line.
1.44 60', 4.35 @ 330, 10.80 @ 122.00 mph.

Problem is it runs out of steam at the top of the first gear.

Running an Edelbrock Super Victor with a Carter AFB 585 cfm, fresh Product Engineering 9500 Fuel Pump and 4 port regulator.

What do you guys think?

[Paul Precht]

Originally Posted by Frank Castros

GT/HA '66 Plymouth Belvedere, 426 Street Wedge, 3,675 lbs.
2.77 first gear ratio, 4.89 rear gear, shifting @ 6,500 rpm, 7,500 rpm at the finish line.
1.44 60', 4.35 @ 330, 10.80 @ 122.00 mph.

Problem is it runs out of steam at the top of the first gear.

Running an Edelbrock Super Victor with a Carter AFB 585 cfm, fresh Product Engineering 9500 Fuel Pump and 4 port regulator.

What do you guys think?

Hi Frank, Jim Hale could be very helpful with that combo but my thought is you're turning it too high, I would go with a 4.56 gear and back to a 2.45 first and advance the cam a little.

[Lee Valentine]

Try shifting 1-2 at 6000-6200 see if it goes faster.

[Ed Wright]

Originally Posted by Lee Valentine

Try shifting 1-2 at 6000-6200 see if it goes faster.

I was thinking the same thing. I always have to get out of low gear much sooner than second.

[Myron Piatek]

Just to be on the safe side, if clearances and other factors allow it, try upping spring pressures a bit. It's better to have a LITTLE more than needed than a little less. Do some research on what your overall engine combo should like in springs.

Being a long stroke big block, it could work better with less rpm, as suggested.

[Frank Castros]

Okay, I'm good with lower rpm, but I'm thinking the intake has too much plenum and runner, agree?

[Ed Wright]

Too much plenum or runner cross section won't cost power at higher RPM. My experience has been the other way around.

[Bob Mulry]

426ci + 525 CFM don't = 7500 rpm at the end or 6500 rpm on the shifts..

Just sayin'


PS:
But I could be wrong......................

[Frank Castros]

Originally Posted by Bob Mulry

426ci + 525 CFM don't = 7500 rpm at the end or 6500 rpm on the shifts..

Just sayin'


PS:
But I could be wrong......................

Please explain your thought.

[Myron Piatek]

Originally Posted by Frank Castros

Please explain your thought.

If I may.....Try breathing through a straw (small carb), then try breathing through the cardboard spool out of a paper towel roll (big carb). You can only take in so much air in so much time through a small hole. The restriction doesn't allow you (or the engine) to breathe enough volume quickly enough to satisfy the needs. (High rpm or you running.)