65mm or 70mm TB?

[CRASH7772]

crash7772 - There are a lot more factors for the torque at 2000rpm than just the throttle body. Stroke/cam/heads/intake/maf/exhaust/etc. Not a valid point

I understand that but the TB isn't going to drop the TQ like larger/smaller runners in the intake/heads or a aggressive cam.

 

[04sleeper]

A friend of mine took his car to Steeda for a dyno comparison between a 65, 70, and 75 mm tb. This was on a 306 with Edelbrock Performer RPM heads, Performer Intake and e-cam, all with a 77mm Pro-M and 1 5/8 LT's w/ 2 1/2" out the back.

The 75 actually lost 2 ft .lbs of torque over the 65 and 70 which made IDENTICAL power and torque.

This was on back to back runs so the 2 ft lbs could be a variance but not close enough to really make a difference.

Most Pro 5.0 cars run a single 90mm TB and are fine making 2400 HP. Do you really think you need a 75?

 

[v8only]

every bit of research that I've done for the gt40/gt40p heads seem to indicate that a 70 is overkill, and that the 65 is perfect. I wouldn't go 70 unless you port the heads or go aluminum. And, stick with the 19 pounders, those 24's are still a little overkill for that combo.

 

[5spd GT]

A friend of mine took his car to Steeda for a dyno comparison between a 65, 70, and 75 mm tb. This was on a 306 with Edelbrock Performer RPM heads, Performer Intake and e-cam, all with a 77mm Pro-M and 1 5/8 LT's w/ 2 1/2" out the back.

The 75 actually lost 2 ft .lbs of torque over the 65 and 70 which made IDENTICAL power and torque.

This was on back to back runs so the 2 ft lbs could be a variance but not close enough to really make a difference.

Most Pro 5.0 cars run a single 90mm TB and are fine making 2400 HP. Do you really think you need a 75?

Interesting...makes me rethink the whole 75mm TB idea I had...

 

[5.0Grunt]

IMHO 65mm is plenty,if you get a cam in the future maybe I'd go 70.But rite now you will love a 65mm accufab..