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curtis73
curtis73 GRM+ Memberand HalfDork
11/12/10 3:47 p.m.

This is a long description. There is a list of specific questions at the bottom if you want to cheat.

I just snagged a 67 Pontiac LeMans for cheap. The body is pretty straight but the floor pans are toast. The interior is completely stripped and has been sitting in a pile in the field next to the LeMans for about 12 years so I doubt much of it is useable.

So, here is my plan for this car. I kinda want to go pro touring with a twist. I want it to be done up like a road race car with ridiculously mean performance. Picture a Trans Am/Nascar kinda build with a daily-driver/race interior. The car was factory-equipped with A/C, PS, and PB and I don't see any need to ditch those amenities, but something will have to be done with the factory "titanic" steering ratio and assist.

Externally I plan on some race-type tubular control arms and box the trailing arms with some mix'n'match from the Afco catalog to keep it inexpensive. I'll need some advice on choosing some components but I'm pretty good at suspension design. Probably do some 17" wheels with appropriately fat rubber.

Inside I'll do carpet and A/C with a modest stereo just so I have some tunes available. I want the interior to look like a vaguely stock interior that someone converted to race: carpet, door panels, aluminum instrument panel with big guages, switch panel instead of factory electronics, etc.

Think of it this way... Take a purpose-built road racer car that you convert to a streetable vehicle. The point is to be a really mean street performer but not so mean that I can't have tunes and A/C.

Its a big contradiction, I know, but its gonna be fun.

  • I haven't decided on a powerplant yet, but 400-500 hp is my target. I've always wanted to build a 455 Buick. I might enjoy driving it more if it had a more modern lightweight powerplant, though. EFI is nice as long as its not too complex. Can anyone think of some nice lightweight engine suggestions that don't include the word "LS1" in it? Anyone have a $500 Viper V10 and T56 sitting around?

  • Cage or not? I probably won't ever race it, but if I decide to show up to an AutoX event it might need to be there. How about the benefits of a cage in terms of weight vs. chassis stiffness? Other GR ideas for stiffening things up without adding lots of weight?

As with all of my projects, I want it to be completely GR. Anyone can bolt on aftermarket stuff, but I thrive on stretching my engineering knowledge. I also want it as cheap as possible, of course. Who doesn't?

Giant Purple Snorklewacker
Giant Purple Snorklewacker SuperDork
11/12/10 3:57 p.m.

Find a used Howe racing chassis and set the Lemans on it. They have all kinds of cheap, strong parts to make it handle HP/TQ as well as stop, turn etc.

jimbbski
jimbbski Reader
11/12/10 4:30 p.m.

http://bringatrailer.com/2009/04/21/rare-sight-1964-pontiac-gto-road-racer/

A Pontiac Tempest/Le mans road racer has been done before. See the above link for more info. It would still be cool though and you could even race it with some vintage racing organizations.

ddavidv
ddavidv SuperDork
11/12/10 4:46 p.m.

I had a '67 LeMans. It's a big car, but it's surprising how heavy it isn't. I think a 64-65 would be a better choice, but that's not what you have. I wonder if you could find a more modern chassis to simply bolt the body onto (Caprice, Crown Vic, etc). That may sound like a lot of work but it probably isn't as bad as you'd think. Chances are you'll have to fix rusted body mounts on it anyway (check the ones in the trunk). They are neat cars and I wish I could have kept mine.

kreb
kreb GRM+ Memberand Dork
11/12/10 5:06 p.m.

Didn't those have the rear transaxle? Just drop in a 928 driveline!

But seriously, those are nice cars. Good luck!

tuna55
tuna55 Dork
11/12/10 5:38 p.m.

I agree!
So you want a Pontiac version of this: http://www.hotrod.com/featuredvehicles/hdrp_0605_1964_holman_moody_ford_fairlane/index.html

Do it. Do it with Pontiac power - that's pretty good nowadays. Hot Rod has a seriously stout Poncho build up this month, but for road racing period correctness, I would totally make it a tri power 389. No cooler Pontiac engine existed on the streets.

Either Hot Rod or Car Craft had a whole bunch of inspirational trans am series pictures. Those cars were art because they weren't art, you know? Do it. Do it now.

curtis73
curtis73 GRM+ Memberand HalfDork
11/12/10 5:46 p.m.

Yeah, older GM intermediates aren't as heavy as they look.

An interesting comparison... a 1974 Ford Maverick with a V8 weighs almost exactly the same as a 2002 STi Suby.

I can find another chassis, but I think that would be more work than I need. I don't need a fully-competent road race vehicle that will be competetive at the races, I want a something that will at least spank most of the cars on the road and make some C6 vettes at least break a sweat to keep up.

a common A-body swap is to use B-body spindles from something like a Caprice. That gets you easy 12" discs with cheap parts (and plentiful aftermarket upgrades) and the taller spindle drastically helps camber gain. I'm hoping I can get the handling I want (for now anyway) with some Afco tubular arms and springs, B-body spindles and brakes, and mix 'n' match junkyard F-body sway bars. As time goes by I'll scrounge CL for some cheap coilovers, aftermarket brakes, etc.

The junkyard has some interesting options for steering as well. Late model B-bodies had a variable ratio 12.5:1 box, and the Caddys even had an electronically controlled variable assist that simply provided less voltage to a valve (and therefore less assist) the faster you went. I think I can engineer a rheostat to adjust my assist on the fly.

Rear axle will need to be addressed. I thought about a T56 transaxle from a vette, but not only would it be an engineering nightmare, have you seen what they get for those differentials these days? Expensive. I'm thinking maybe something like an 8.8 from an explorer.

What are your guys' thoughts on a dog box tranny for the street? Plausible? Skip it?

curtis73
curtis73 GRM+ Memberand HalfDork
11/12/10 5:55 p.m.
tuna55 wrote: I agree! So you want a Pontiac version of this: http://www.hotrod.com/featuredvehicles/hdrp_0605_1964_holman_moody_ford_fairlane/index.html

Exactly, but with four seats, A/C, and carpet

Do it. Do it with Pontiac power - that's pretty good nowadays. Hot Rod has a seriously stout Poncho build up this month, but for road racing period correctness, I would totally make it a tri power 389. No cooler Pontiac engine existed on the streets.

I love me some Poncho power, but its heavy and long-stroked. If I'm dusting a Viper on an onramp, I want to hold it at 7000 rpm in third and have 500 rpm left to go when I roll on the throttle after the apex.

Those cars were art because they weren't art, you know? Do it. Do it now.

Well said. I'm gonna make it happen one way or another... even if I keep the stock 326 and powerglide for now

LS1 would be the quickest way for me to get a lightweight 450 hp and an easy drop-in, but I'm rebelling against it because "everybody" does an LS1 swap these days.

btp76
btp76 Reader
11/12/10 5:55 p.m.

There have been guys who've put the Mustang 8.8 in G bodies. I don't know if anyone has done the same in the early A bodies. I wouldn't bother though as coil spring 12 bolts aren't hard to find. Also, they used the 8.5 ten bolt in some 71 - 72 Cutlasses and Skylarks.

We did a poor man's 3 link in one of the LeMons cars and it made a world of difference. Search PM3L on Corral.net and corner carvers.

BoxheadTim
BoxheadTim GRM+ Memberand Dork
11/12/10 6:36 p.m.
curtis73 wrote: What are your guys' thoughts on a dog box tranny for the street? Plausible? Skip it?

I assume you're talking dog leg shift like this?

R 2 4

1 3 5

I DD'd a 924 with a box like that for a while - you get used to it fairly quickly and then don't really notice it anymore.

tuna55
tuna55 Dork
11/12/10 6:43 p.m.
curtis73 wrote:
Do it. Do it with Pontiac power - that's pretty good nowadays. Hot Rod has a seriously stout Poncho build up this month, but for road racing period correctness, I would totally make it a tri power 389. No cooler Pontiac engine existed on the streets.
I love me some Poncho power, but its heavy and long-stroked. If I'm dusting a Viper on an onramp, I want to hold it at 7000 rpm in third and have 500 rpm left to go when I roll on the throttle after the apex.

Don't underestimate those engines. Look in super stock for examples, they can easily be built to rev to whatever you want. I maintain that stroke doesn't preclude RPM, metallurgy does. Get good rods, a good crank, a girdle or some cross bolted mains and the valvetrain to match and 7500 will be no sweat, I promise. They're not really as RPM sensitive as Honda lovers would have you believe. Get awesome heads and a cam and it'll actually be useful up there too. The tri power when you pop the hood would be awesome. Just imagine that pissed off C5 Z06 owner who walks by in the paddock and looks under your hood. If he sees a Viper V10, he'll have an excuse. If he sees a carbureted (even if you covertly convert it to injection) 389 under there you're going to get some serious respect. They're not really any heavier than a small block either, and with aluminum heads, intake water pump, oil pan, and headers, you'll be surprised how much they don't weigh. Period correct is the way to go for this one.

Rad_Capz
Rad_Capz Reader
11/12/10 6:45 p.m.

You need to check out Dons car http://www.pro-touring.com/forum/showthread.php?58135-GTO-road-race-video-at-Pocono-Speedway&highlight=road+race+GTO

I like the idea of keeping it Pontiac powered. That's what I did with my Firebird. You can build a nice engine out of a early 400 block. LS is the trend though.

If you're not going to track it skip the cage. A rollbar maybe, but a cage is a pain on a street car. I crawl in and out of mine a lot and it gets old.

forzav12
forzav12 Reader
11/12/10 6:50 p.m.

Check out the Grey Ghost. Pontiac trans am car built back in the day by a bunch of off-duty GM engineers. I believe they started with Herb Adam's wife's old '64 Tempest. Huge fan favorite and would actually have won a race against all the factory teams except the amateurs sucked at pit stops. Easy to make one fast and handle well.

Rob_Mopar
Rob_Mopar Reader
11/12/10 7:23 p.m.

Forzav12 beat me to the Grey Ghost. Granted it's the boxier Tempest, but it's good inspiration.

I have as soft spot for the '66-67 A-body Pontiacs. My good buddy has '66 Tempest convertible he's had since we were in junior's in high school. My old boss has a '67 GTO convertible. I was helping him out with it last weekend.

I think the later fast ratio Saginaw boxes from the '80's Monte SS bolt in. Not 100% sure on that.

For the rear, there are several aftermarket options. I think there's more than one place making 9" Ford housings that bolt in. That opens up a ton of aftermarket gear selections and an easy way to change ratios for the track or street.

I believe someone has a new Chevy 12 bolt housing available, and I know I just saw an ad for a new Dana 60 style for the GM A-bodies. If you go with a T56 the swapability of the center of the rear is less of an issue.

I too vote for a Pontiac motor under the hood. Edelbrock has aluminum heads. Somebody has an aluminum block but they cost. I believe there are retrofit roller cams available too. Paint it all Pontiac engine blue to be a little stealth.

novaderrik
novaderrik HalfDork
11/12/10 8:04 p.m.

there are a lot of things you can do to the A body to make it do pretty much whatever you want it to do. it is the same chassis as the Chevelle, and there are a lot of good and cheap suspension pieces for them.

i'm sure there are a lot more good sites out there, but here are a couple of good sites for GM A bodies:

http://www.pro-touring.com/forum/

http://www.chevelles.com/forums/ (look in the pro touring and suspension sections of the forum)

tuna55
tuna55 Dork
11/12/10 8:33 p.m.
curtis73 wrote: Rear axle will need to be addressed. I thought about a T56 transaxle from a vette, but not only would it be an engineering nightmare, have you seen what they get for those differentials these days? Expensive. I'm thinking maybe something like an 8.8 from an explorer. What are your guys' thoughts on a dog box tranny for the street? Plausible? Skip it?

The dog box would be neat, but only neat. If you're into novelties, go for it. Liberty or whatever makes a nice one, but you're spending a lot. If it were me I'd do a gear vendors OD on a muncie 4 speed. That way it would be driveable on the street but it would still be a classic four speed. Those were actually really good transmissions.

stuart in mn
stuart in mn SuperDork
11/12/10 10:32 p.m.
Rad_Capz wrote: You need to check out Dons car http://www.pro-touring.com/forum/showthread.php?58135-GTO-road-race-video-at-Pocono-Speedway&highlight=road+race+GTO I like the idea of keeping it Pontiac powered. That's what I did with my Firebird. You can build a nice engine out of a early 400 block. LS is the trend though. If you're not going to track it skip the cage. A rollbar maybe, but a cage is a pain on a street car. I crawl in and out of mine a lot and it gets old.

That's the car I was going to post (his website is here: http://www.gtoroadracer.com/)

I'll put in another vote for a real Pontiac engine. Making them run to 7,000 can be done, but it's expensive and probably not necessary; they can make more than enough power without having to rev that high. I know a number of guys who have 500+hp engines in their street cars that idle like stockers, you can get a lot more out of them than that for a race engine.

Wally
Wally GRM+ Memberand SuperDork
11/13/10 12:36 a.m.

The first GRM I was given had an article on I think two brothers that ran a Chevelle and GTO in the Northeast. maybe someone can remind us what issue they were in as the back issue would probably hae some good ideas.

Woody
Woody GRM+ Memberand SuperDork
11/13/10 5:12 a.m.
Wally wrote: The first GRM I was given had an article on I think two brothers that ran a Chevelle and GTO in the Northeast. maybe someone can remind us what issue they were in as the back issue would probably hae some good ideas.

I don't remember that article, but it sounds like the Murray Bros. They used to run a mid-60's Chevelle at Lime Rock in the late 80's or early 90's. I laughed at it the first time I saw them trailering it into the pits.

Then they set FTD.

http://murraybrothersgarage.com/murraybrothersgarage.html

Check out some of Andrew's work:

STS_ZX2
STS_ZX2 New Reader
11/13/10 5:44 a.m.

Schwartz Performance.

http://www.gmachinechassis.com/

tuna55
tuna55 Dork
11/13/10 5:54 a.m.
STS_ZX2 wrote: Schwartz Performance. http://www.gmachinechassis.com/

That is a good idea. Seriously.

minimac
minimac SuperDork
11/13/10 7:07 a.m.

Since the frame is the same as was used on the chevelle, bolt on parts for roundys /road racers abound and are cheap. If you want to do this on the cheap, attend one of the many racers auctions that are held all over the country, when roundy season is over. Bargains can be had for stupid cheap money. GPS suggested a Howe chassis-the trouble with that (or a Dillon or Troyer)is that they are swiss cheesed and weight biased to the left.Unless you can find an old(30 years) upright asphalt modified chassis. You still would have to cut the front end off and weld in a GM front clip, although camaro/firebird frontends can be found cheap. I wouldn't do a full cage, but a single hoop w/fore and aft bars for stiffening. D.I.Y. long trailing bar (nascar type) rear, tubular a-frames front, Big Block poncho power(although big chebby would be cheaper), I like it!

DirtyBird222
DirtyBird222 SuperDork
11/13/10 7:44 a.m.

then be a rebel and build a turbo 5.3 LM7 out of a truck. There's a guy that has a stock 5.3 bottom end (with 130k miles on it) shoehorned into a 1g Rx-7 with a massive turbo running 8.90s. I know you don't care about 1/4 times, but it's just a reference to what you can do with it. It's technically not called and LS1, plus the engine name has the same initials as the car itself so it's a perfect match plus you get the cool "LS" technology and can mix and match parts. DO IT, BE A REBEL!

Giant Purple Snorklewacker
Giant Purple Snorklewacker SuperDork
11/13/10 8:59 a.m.
minimac wrote: ... GPS suggested a Howe chassis-the trouble with that (or a Dillon or Troyer)is that they are swiss cheesed and weight biased to the left.

I believe they offer non-offset chassis used for road racing. If that is not the case... get an old chassis from the v8stockcar.com guys or the ARCA road race series. While you don't really need a full-on race car - it offers good, solid geometry and off-the-shelf parts designed to handle anything you can throw at it. I see fully kitted offset rollers with tons of goodies going for kart money. So, you swap all the goodies onto a non-offset tube chassis, set on cool Pontiac body... add engine. (I am projecting, BTW... because I think it would be awesome. I only marginally considered your actual goals )

minimac: Do you know who supplies those RR ARCA or V8 Stockcar series chassis? The googles are failing me right now.

curtis73
curtis73 GRM+ Memberand HalfDork
11/13/10 10:25 a.m.
BoxheadTim wrote: I assume you're talking dog leg shift like this? R 2 4 1 3 5

Actually I'm talking about a tranny with dog rings instead of synchros. Like rally racers use.

You guys are coming up with some awesome ideas! I like the idea of a used race chassis. That Gmachinechassis.com is sweet.

I'm also going to stick to my guns for now on the lighter engine. A fully dressed 400 pontiac is north of 700 lbs, but an LS1 is just north of 450 lbs. That's a big difference. I can't think of any lightweight engines that would be an easy swap (other than LS1) so I might stick with the Pontiac, but I'm pretty keen on going with a different engine.

Think of it this way - if I'm keeping PS, PB, and AC, I want to give up weight elsewhere and the engine is a good place to shave weight.

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