Oshawa built 1971 A-body's (Lemans,T-37 or Lemans Sports) with 455 HO

455Lemans · Veteran Member

RE: Oshawa built 1971 A-body's (Lemans,T-37 or Lemans Sports) with 455 HO

455Lemans · Veteran Member

Forgot one!

Astro Jet · Poncho Master!

455Lemans wrote:

Here's my "Bobcat" .....
Ran a 13.92 @ 108 mph last summer with closed exhaust and street tires. Can't wait to uncork the headers, put on some slicks and try again this summer!

What has been done to your motor? Judging from your trap speed, you must be putting out at least 350 hp to the rear wheels. Do you remember what your 60 foots were? Improving your launch, especially with the slicks, should bring you down to the low 13's easily. What is your rear end ratio?

Astro Jet · Poncho Master!

455Lemans wrote:

Yes, it was Keith's car. I finished it off with the rocker moldings and the emblems. It's been a great car!

Is your name Steve? I think we may have met at Mapleview in Sept. of 07. Is it your car that is in the Reader's Rides section of Hot Rods & Classics?

Canadian Poncho · A Poncho Legend!

Very nice!

Todd

455Lemans · Veteran Member

Ya, that's me...
And that's my car in Hot Rods and Classics, although I live in Hamilton not Burlington.....
Other than the '70 Laurentian, what else do you own? I don't really remember you from Mapleview. Were you driving the Laurentian?

My 455 is a '70 block and #64 heads 87 cc chambers (2.11 intake 1.77 exhaust) 370 horse stock, but now has a Comp Cams .480/.480 cam 280 degrees duration and a set of hedders.
Trans is a BW T-10 rear is a 12 bolt 3:55 posi. Hence the high trap speed. Only problem is, I kept spinning the damn belts off the pulleys! (5500 rpm). That and a starter that hates the heat. (Typical Poncho) I'll be doing a few mods in the spring including a new mini high torque starter and a larger deep groove alt. pulley. I have a set of "anti hop" bars that install on the upper rear control arms, but "wheel hop" really isn't an issue. Once I get all this stuff done, we'll give her another try. Fingers crossed I don't blow up the Bobcat!
My previous car was an '81 Z/28 350 4-speed, but the LeMans is much quicker and ALOT more comfortable.

427carl · A Poncho Legend!

427carl wrote:

455Lemans · Veteran Member

Just a quick question for you "techies" out there. My LeMans has a 3:55 12 bolt rear. I want to take it on a long trip this summer and I'd like to go to a smaller gear set (ratio). Is it possible to put 2:73's in this rear end or would I need to change the carrier? What is the smallest ratio I can go with?
Thanks, Steve...

CdnGMfan · Canadian Poncho Superstar!

The rear in your car is probably the Chevrolet type 12-bolt 8.875" ring gear. While a 2.73 was offered, I'm not sure how much modification it will take for the r&p swap to take it into the 2-series (it may be a different carrier for the 2-series gearing). A simpler swap that would reduce your revs would be a 3.07:1 gearset. Your torqey 455 will still treat a 3.07 ratio as a performance ratio but the revs will drop on the highway.

The Chevrolet 12-bolt was stock with all U.S.-built 455-powered Lemans at that time. As I have been hearing, Canadian-built cars may have also used that rearend behind the 400s as well (rather than the 8.5" 10-bolt, not to be confused with the weaker Chevy 8.2" 10-bolt)

I notice that you spin your 455 to 5500 rpm. I would say that is really pushing a round port 455. 5000 might be a prudent redline. They have high piston mass and due to the long stroke 455 crank, high piston speeds. The only 455 I would feel safe taking beyond 5000 rpm would be a SD-455.

455Lemans · Veteran Member

Thanks, Cameron. That's what I figured. I believe my carrier is a series 3, and I read that they used that carrier for 3 + ratios only. I'll look for a 3:07 ratio set.
Ya, I was really pushing that 455. Spun the belts right off the pulleys. Using the stock tach as a guide, I would imagine I might have been spinning it faster than 5500. I've heard the stock tachs have a tendency to read low. I don't want to blow this puppy up. I really need to get my 400 back together. It'll have a beefier bottom end when I'm done with it. Know anybody with a set of R/A V heads? LOL! They'd be worth more than my car....
Thanks again...

427carl · A Poncho Legend!

455Lemans wrote:

I want to take it on a long trip this summer and I'd

bolt a couple of oversize tires on, for the trip... use your tach as a speedo

455Lemans · Veteran Member

I'm actually thinking of going on the Hot Rod Power Tour. Not the whole thing, but for a few days. I do have a taller set of tires, and I'll use those in conjuction with the 3.08's. If I can keep the rev's to around 2500, I'd be happy and so would my gas tank! The 455 is no HYBRID that's for sure.
Thanks for your help on this, guys, much appreciated.

Astro Jet · Poncho Master!

To use 2 series gears you would have to use a 2 series carrier because the ring gear is so much bigger than on the 3 series. Not worth it switching carriers for just doing one trip in my humble opinion. As others have stated, 3.07's are probably your best bet with a taller tire. What is the average speed on the power tour?

65Camino · Uber Guru

Taller tires is the best answer. Cheaper and easier to do. When you get back from the Power Tour just change them back.

Noticed you mentioned about changing your starter because of the hot start issue. Wire in a Ford starter on the fender or put in a heat shield.

73SC · A Poncho Legend!

65Camino wrote:

Taller tires is the best answer. Cheaper and easier to do. When you get back from the Power Tour just change them back.

Noticed you mentioned about changing your starter because of the hot start issue. Wire in a Ford starter solenoid on the fender or put in a heat shield.

Found in internet - What you need to do;

Get a Ford starter solenoid, of course.
- These units ground through the bracket. For fool-proof grounding, run a well grounded wire to one of the screws you use to secure the solenoid to the firewall.
- If you are adamant about not having any Ford parts on your General Motors product, simply visit your favorite AC Delco parts house and purchase p/n U939.
- You can use just about any Ford starter solenoid, later model cars came with a stubby unit with all the terminals opposite the mounting flange, such as found on 1987 and newer Ford Crown Vics and Mercury Grand Marquis. (until 1996 or so when Ford went to the starter mounted solenoid like the Pontiac your converting. Go figure.)

Relocate ALL the wires that are currently connected to the BAT terminal on your starter (the large terminal) to the 'hot' side of the Ford solenoid (that's the side connected to the battery, typically the large post to the left on the Ford solenoid)
- This will allow you to relocate the wires away from the headers and hot engine block. You will only have a SINGLE cable running to the starter, not a bunch of wires.

Relocate the 'start' wire on the starter solenoid (small terminal closest to the engine) to the 'S' terminal on the ford solenoid.

Run a new heavy guage wire (battery cable) from the right side (non-hot) of the Ford solenoid to the BAT terminal on the starter (the large terminal).

Run a wire or short the "S" terminal to the "BAT" on the stock GM solenoid. This way, the solenoid is getting FULL battery voltage to the solenoid.

-- Edited by 73SC at 20:48, 2009-02-23

455Lemans · Veteran Member

I'm going to use a geared high torque mini starter. No FoMoCo for me, thanks....Above seems like an awful lot of messing around with wires. Wires that I would prefere stay as they are.

Astro Jet · Poncho Master!

I'm with you, no FoMoCo solenoids cluttering up my inner fenders!