Advise on Ford 302- 331/347

[1795]

Originally Posted by moore_rb

My car will climb a 10% grade in 4th gear, at +3500 feet elevation, doing 65-75mph, without issues. It doesn't lug, and it feels strong.

However, you are correct that If I am running through the mountain curves in a more spirited manner, then 3rd gear makes both me, and the car, much happier...

The rear gearing has to be balanced to the transmission. With a Toploader (or a non-overdrive Richmond 5-speed), 3.31's or 3.42's are just about perfectly suited to the internal ratios in the transmission (again, JMHO).

With an overdrive 5 speed (TKO or T5)- you have to calculate the correct rear end ratio based on the specific ratios used for 1st and 5th gears in your particular gearbox (Especially with the T5's, because there are so many different T5 gear sets out there).

Zarpox says he has a WC- T5 with the 2.95 first gear, and the .73 overdrive... This is the exact same trans I had in my previous green car (which also had a 302 that ran out of breath early, and could barely turn 6000RPM).

I ran 3.73 rear gears in that car (with the same 295/50 rear tires) and the overdrive was perfect, but 1st gear was REALLY short- I had to shift almost immediately (at about 30mph) under WOT acceleration. I always felt like 3.55's (or possibly 3.42's) would have probably been better choices for that engine and transmission combo.

I
I concur regarding the rear-end ratio. I had a top loader with a 3:54 rear end and I thought that it was the perfect combination. Engines are much happier when they are running in the middle of their power band, then when they are at the bottom of it.

Good point about being careful that he is not running an engine at the upper end of the power rating of the transmission. It eventually will catch up with you if components are run at the maximum of their capability.

[Kit Coyle]

I agree with Robert Moore. I have a 1970 BOSS 302 engine updated with
a solid roller cam good for around 400 hp. The rear is 3:31 and the Tremec
TKO has a 2:95 first gear which feels a bit short. If I went any lower in the
rear first gear would be a pain to use. The little Cleveland will pull past
7000rpm easily but the cam puts my peak hp at about 6500 and peak torque
at 4100rpm. On the freeway in 5th gear I see about 2200rpm at 70mph. The
car feels happy at slow speeds around town and never bulks. It feels like
a 4 speed toploader with over drive...which it essentially is! Whats not to like?

[cwhoofgatorr]

WELL I'll say this... Lance built my current engine and it a beast as far as I am concerned. 331, AFR 165 heads, Ford X cam, RPM air gap intake. 3:55 gears and I can't mat it any gear under forth. OH by the way Holley Terminator EFI and love it. I can run the mountains, flat land and just cruise. Could not be happier cars really gets with it and will spin the tires at will.. So far with 400 miles on the engine, averaging 19 MPG and that's getting on with it: Car pulls right to 6500 strong and I can't see any need for more power on a street car. If I remember right it's 10.1 Comp. JMHO. 3DSMILE: