Converting to carburetor
- Thread starter Jarhead67
- Start date
85GTStangGuy
5 Year Member
750 cfm is not to big.
Jet it for the needs of the engine and let it eat.
Jet it for the needs of the engine and let it eat.
I ran an 830 cfm Carb Shop carb on my 306 and now its on the 351 just jetted different.
wbrockstar
Member
85GTStangGuy
5 Year Member
The larger carbs, while certainly tunable for a specific application, will still sacrifice some lower rpm throttle response due to the lower air velocities through the larger venturis.
Engineering-wise, a 331 would need to be spinning north of 7500 rpm before 750 cfm would be consumed. And even that's with a volumetric efficiency that is probably not going to be seen on a street engine. Theoretically, of course.
That's my 2 cents worth (and that's probably over-paying for it too).
Engineering-wise, a 331 would need to be spinning north of 7500 rpm before 750 cfm would be consumed. And even that's with a volumetric efficiency that is probably not going to be seen on a street engine. Theoretically, of course.
That's my 2 cents worth (and that's probably over-paying for it too).
If I had efi, I would keep it and tune with it. I plan a Holley efi system on my 82 as soon as I can get there.
That said, my 331 with AFR 185s, dynoed at 415hp and 415 tq, on an engine dyno, using a 600 cfm Holley 80457 vacuum secondary carb. AF ratio was good all through the rev range to 6200. Dyno shop said it did not need a bigger carb or other stuff.
That said, my 331 with AFR 185s, dynoed at 415hp and 415 tq, on an engine dyno, using a 600 cfm Holley 80457 vacuum secondary carb. AF ratio was good all through the rev range to 6200. Dyno shop said it did not need a bigger carb or other stuff.
Sounds like you’ve got yours dialed in. I’m not making any decision on mine yet, I’m taking another route. My problem is that my engine quits making power at about 4,000 rpm. I’ve replaced the entire electrical system with MSD, Holly and Terminator X with no improvement. If it’s not electrical, ignition wise, I figure it may be mechanical, as in the valve train. When I built the engine we used GT40 3 bar heads. Everyone thought that those heads just weren’t enough to make the power I wanted, they’d hold me back. I wish I had listened.
Done a lot of reading about high rpm valve float which could be causing my problems.
I’ve made the decision to replace my GT40 heads with Liberty aluminum 185 heads, and the lifters with Ford Performance hyd roller lifters.
From where?
I just looked at what I "think" is their website and it looks shady as eff.
Is this it? https://www.libertyperformance.com/
No address
No contact number
Only way to contact is by email?
Nope
Have you done business with them before?
If you set up an account you are able to contact them.
My builder has used their heads with good luck. The only thing he doesn’t like are their rockers, but I was planning to use Scorpion.
Rog. So long as you got the info on them.
I may email them a, "Dude, looks shady without this info" message.
Looking forward to your review of their stuff. Never heard of them before (obviously).
