sprint six swap to 455
 

i have a 66 sprint six lamans and want to put a 455 in it does anyone know what i will need to do.thanks jeff

Welcome Jeff. It can be done. But my bet is most will tell you not to.That sprint six was way ahead of its time & a very cool engine. How many have you seen at a car show? When I see one I'm all over it. But it is your car so good luck on it. Saltman

iam not 100% certain but i think the mounts were different and you may just need some v-8 mounts for the same car, if there not it different it should be a simple swap

You will need:
V-8 Engine and frame mounts.
A V-8 battery tray as the starter is on the opposite side.
Fuel line will need to be moved to opposite side of car, and it wouldn't hurt to change from 5/16 to 3/8".
A bigger radiator.
V-8 coil springs for the front.
A V-8 throttle cable, as the six-cylinder throttle cable is too long for the V-8.
A v-8 throttle cable bracket.
You will need to modify the 6-cyl. wiring harness or replace it with a V-8 harness.
Depending on what your engine came out of, you may need an A-body oil filter adapter that tilts away from the frame.
Exhaust system.

My first question is the car a true "SPRINT" or just a base OHC 6 that was turned into a sprint? If you have a true sprint then doing so is IMO foolish.

The list above is a start but remember if the ol' gal is a true OHC model then she may develop complications from the transplant :D

If she's real DON'T DO IT! but if you must then save/preserve everything if possible.

I agree with Jeff. A rare breed indeed. Save It.

Tim john---

Sprint cars are SWEET! I would love to get hold of a sprint engine, add an inexpensive overdrive 5 speed like George K did. Sounds like a lot of fun.

By the way, welcome to THE Pontiac forum. People would love to see some pics of your car too.

As eluded to, I had a '67 Lemans Sprint that had a 3.90 posi axle and I installed a late '70's GM 5 speed OD into it. Loved driving that car.

I now have a '67 GTO, but if i came across a nice Sprint, I May be convinced...........you just don't see many.

Your car, tho, but save the parts.

George

Hey Jeff,
I hate to pile on but...
If you have a real sprint with the original motor and want a cammy GTO beast to blast around in (who doesn't? ;-) ), sell the sprint, buy a good driver GTO and use the left-over cash for gas.
Or, do what ever you want. As stated by others, we love those sprints.
What kind of cash would a number's matching Sprint fetch these days? I haven't noticed one for sale in quite a while.

I had a 66 Sprint and I did put a 400 in it, but that was way back in the day. Some things to consider. You will need to change the frame engine mounts. The fuel line is on the other side so you need to run about 3 feet of fuel line. Also the battery need to be switched from the right side to the left. Other than that it's a snap, but I'd also remmomend DON'T DO IT. The Sprint 6 is a very rare car these days.

Aside from there being OHC6 websites, there is Primatech http://primatechmotorsports.com/ which specializes in Sprint engines.

OHC 6 swap
 

Hi Jeff
Welcome to the PY forums.
It's a Great site with lots of information about almost everything Pontiac.
I'm constantly amazed when it comes to some of the knowledge most people on the board have. I have yet to post a question that doesn't get answered multiple times.

I'll chime in with the others about keeping it an OHC 6
Great cars and well ahead of their time.

That said, I'm doing the exact opposite of what you want to do.
I have a 67 Lemans convertible which originally had a 326 V8 with a 2 speed auto.
The motor and trans were long gone when I bought the car, but I had a few 400 blocks and plenty of heads to build a strong V8 street machine.
I went to a car show over a year ago and saw a true 1966 Lemans OHC Sprint 6 and fell in love with the motor all over again.
I talked with the owner for over an hour until he finally offered me a ride in his at the end of the show.
I became a believer in the "Cammer" motor. :)
I'm now in the process of converting my 67 Lemans into a "Sprint" Clone convertible with a 5 speed trans, factory A/C and a 3:23 posi rear. ;)

Now, the reason for the long reply.
If you decide you really want to go through with the V8 change over, I would like to trade you some parts.
I have the V8 frame mounts from my car to trade with your OHC frame mounts.
I also should have most everything linkage wise to install the V8.

Let me know if you are interested.

I'll end by saying one more time, Keep it as a Sprint 6!
It's your car, so have fun with it whatever you decide to do

Ron

I would rip out that old 3/4 of a motor and 4spd and put in a "Real motor" with a tremec 5spd. May be Global west and Hotchkis for the suspension and have some guy named Craig paint the HELL out of it!!!! But thats just my .02

Agreed if you have no real machanical ability then the easy way out is to do the swap :D
The OHC isn't the most dependable engine, and most don't take the time to learn about the in's & out's.
I myself learned the hard way. Do I know everything NOPE.
It is a love it or hate it engine, but now that I have a better knowlage of them I would not take it out for nothing.

Draws them in at almost every event.
Don't be fooled by all the shiny parts I drive the hell out it and have broken lots of stuff :D but man she is a fun well balanced car to drive, those overweight v8's cause many a good pontiac to drive like sh!t ;)

All joking aside, whatever you do save them parts.

Best of luck.

It's been 40 years since I heard one run. What does the exhaust sound like? Can you get it sounding sweet?

OHC 6
 

Jeff Leonard
Thanks for the reply.
I didn't realize that you bought a roller sans drive train.
Still could use the OHC frame mounts if you are not going to need them . ;)

Jeff Hamlin
I hope my engine compartments looks half as good as yours when I'm done with my OHC 6 swap.
Sweet :)

Regards
Ron

Zoom Zoom...
 

I've tried to stay as close to stock as possible. I have the 28”X4" round muffler with the resonator and the stock trumpet tip.
I think It sounds the way John D. wanted it to, like a high revving import.

A few years back I had my back glass out for some repairs and It was really the first time I heard the full effect of the exhaust notes,
I love it!

Motor
 

Arbys, I bet it sounds something like "vroom, Vroooom, VROOOOOMMM"!

My 67 tempest sprint has a clifford headers with true dual exhaust sound like a mellow v8 to me . It is a bare bones car Sprint 3 speed with only ac as a option but Rare Plum Mist Paint code. It A a project I decided to keep only missing the original carb and exhaust manifolds and still looking for them . My son wants me to put my 500 horse 455 roller motor in the car and have fun , but it like my Judge keeping it original. Just find a tempest or lemans without a motor and have fun.

vroom, vrooom, yes but...
I haven't really had the ball$ to take up to VROOOOOM!

I wiped a cam several years back and never really got over it :(
Good news is cams aren't as hard to find now,but I'm still holding back.

OHC 6 swap
 

Jeff
really like your rally dash with the 6500 RPM redline

I'm not trying to destroy this thread, but what difference is there between a 66 & 67 OHC Rally dash other than the 60-80 lb oil pressure gauge?
I found this 66 unit, but mine is a 67.
I'm going to keep it until I find a correct, decent 67 Rally Dash unit that I can afford ;)

I think that because the Sprint cars are so rare at car shows, Most people who look at it won't know any difference between the years.
Ron