3.55 vs 3.73 gear th350 trans 26.1 inch tire

[skar]

I went with a 3.55 gear. With a 26.1 dia. tire it will spin about 3000 RPM at 65 mph. I think a 3.73 would have been a tad to much for a th350 trans, and my tire size.? Some day I will get a overdrive trans they have a lower 1st gear from what I have been told. I also hope this 10 bolt holds up. Also told if built with good stuff a 10 bolt with a auto and street tires is good for 400 SAE HP.

[csmith4153]

I have a 3.55 12 bolt in my 69. Seems to be a good ratio for my combo. It has a 500hp 427 and a 4 speed.

[skar]

500 hp needs a good 12 bolt. ( I would say)

[csmith4153]

It will fry the rear tires! I scare everyone that goes for a ride. It needs more tire in the back.

[skar]

I bet it does . Sounds like a nice car. ( No replacement for displacement)

[CHEV 383]

Gears

I am running 3.31 gears in a stock 12-bolt rear end. I'm also running a 383 with a 4-speed (saginaw I believe) transmission. Not your best off the line, but still able to fry the rubber on demand.

If and when the overdrive tranny is an option, I will do the homework on gears and tranny combo and make it one big swap.

I don't have the specs on my tires, but I am running 15" stock rim, with 10" wide tires. I could probably get a little bigger under there without looking odd.

ORT-2

[skar]

[quote=CHEV 383;189016]

? How do you like your 383. Did you build it or had made locally.
or crate motor. I am slowly looking into getting one for my car.

[csmith4153]

I am slowly looking into getting one for my car.

When you get ready, I'll hook you up with parts. Chev 383 got a good deal from me on his headers and oil pan gasket.

[skar]

cool

[CHEV 383]

I love the 383. I had it built by a guy I knew in Detroit, on the side. He did the boring and installed the crank, pistons, intake, oil pan, ect. I did a lot of the decision making, with his guidance, on parts and brands. I spent almost $5500 from start to finish, with all the chrome and name brand items. In my opinion, if I knew that I was going to spend that much, I would have bought a crate motor from a source online or locally, and probably gotten more power. I see turn-key motors for the same that I paid running at 450 hp. If you don't go big block, stroker is the only way to go. Unless you want a high-revving engine. gobs of torque, and hardly need to get into the secondaries in my carb during normal driving. When you start looking for a motor, or want to start pricing one out, go buy a Chevy highperformance magazine and look at all the ads in there for crate motors. That will give you a good head start.

By the way, CS3 hooked me up!!!!! Great guy to work with.

ORT-2

[Orange Terror]

What 10 bolt do you have Skar? The 8.2"?

[skar]

What 10 bolt do you have Skar? The 8.2"?

Yes 8.2 that came with the car.

[Orange Terror]

Yes 8.2 that came with the car.

Yeah, IIRC those aren't known to be terribly strong. I would definitely include a 12 bolt in my budget if you are going to build a 400+ hp motor.

[skar]

I talked to all 4 of the big boys DTS , moser,strange,
They all said with street tires only and with a auto trans, a 400Hp (SAE)small block would be fine with a good gear manufacture and a limited slip .

I went with a Auburn pro and Richmond 3.55.
Motor city steel also said it would be fine.???? (They did the install)Also have a aluminum performance cover for the differential..