[Slow&Easy1]

I bought a somewhat rust free 70 LeMans Sport convertible a couple months ago. Has A/C, power steering, power drum brakes, 350/350, console, and tinted glass. It was taken care of really well. The body had small patches of rust along the weld seams of the rear panels and a couple small holes in various places of the outer wheel houses and trunk floor. The car came with the heavy duty frame which was in very good condition. The front fenders inside structure is rusted, the bottom of the core support also, and the car was hit at some point a long time ago hence the repaint and replaced parts on the front drivers side
Anyway, I drove it around some and it is good, actually awesome, but I kept thinking the holes in the panels will only get worse. So I completely disassembled the car - took lots of photos - and had the body and frame sandblasted. The front 2/3’s of the body is perfect, only needed a small patch along the top of windshield frame. The back needed some panel pieces and patches to get it all as good as new. That job is not done yet but is progressing nicely.
The Plan. I will hopefully drive the wheels off it cruising and an occasional burn out. I like the idea of stock but the original motor was gone before I got it and a GTO front end will be easier for me to accumulate vs LeMans, in fact it’s already here. I didn’t set out to build a clone car but that’s where I’m at now
I’ve gotten the GTO front end- aftermarket fenders, hood, and core support and a used endura bumper and brackets and an NOS valance panel I bought in 1990. I’ve also already gotten the disc brake conversion kit and new stuff for rear drum brakes among other things.
I have read threads on this forum and it’s been a great source of information and motivation.

 

[tjs72goat]

That will be nice when done.

 

[1968gto421]

Nice work. I would be tempted to use the LeMans Sport logos on it rather than GTO to mess with peoples' heads. IMHO After all the '64, '71, '72 GTO front ends were just options on the LeMans. But it is your car so your the judge on how to do her. Gotta admit, you do nice work.

 

[Slow&Easy1]

I was thinking the same thing about the logos but I was leaning toward no logos - almost certain there will be no GTO logos. I’ve got plenty of time to sort that out. Planning to use the 350 block and heads with a longer stroke crank, roller cam and 068 intake with quadrajet while changing out the TH350 and 2.78 open ten bolt with a 200-4r and a 3.70 Ford 9” posi. That should be good for cruising around. I am interested whether anyone has experience or advice on a similar driveline.

 

[PontiacJim]

I was thinking the same thing about the logos but I was leaning toward no logos - almost certain there will be no GTO logos. I’ve got plenty of time to sort that out. Planning to use the 350 block and heads with a longer stroke crank, roller cam and 068 intake with quadrajet while changing out the TH350 and 2.78 open ten bolt with a 200-4r and a 3.70 Ford 9” posi. That should be good for cruising around. I am interested whether anyone has experience or advice on a similar driveline.

Sounds like a plan. No need to ditch the 350, in my opinion, but many will push to go the 400CI route as your base and then build from there as you can pull more power for about the same cost. True, but first you have to hopefully find a good block or complete engine and these don't seem to come cheap anymore. Most just look for a block as you really are not going to use much more unless you got lucky and have an engine with the large valve/screw-in studs - but price usually goes up as most know what they have thanks to the internet info.

If you only have a 400CI block, you can fit it with a complete rotating assembly reasonable enough. But then you need to add all your other goodies, heads, intake, carb, distributor, timing cover, pan, etc.. This begins to add up versus having a complete engine so you don't have to at least scrounge the small parts.

The other option is to purchase a rebuilt engine from one of the Pontiac builders. Some can be reasonable, but I just prefer to build my own as that is part of the "fun" for me - even if I screw something up. :yesnod:

Assume you are doing the Butler 407-413CI stroker kit? Pretty good price as well. The only problem ( not really a problem) is the factory 350CI heads if you use them. The small valves and press-in studs will be your limiting factor - unless you plan on using better heads which is what I would recommend. You could add screw-in rocker arm studs and size up the valves which is an option to your heads if you choose to use your heads. As far as I know the 1970 350 blocks will have the scallop cut into the cylinder bore for the larger 2.11" intake valve.

It looks like they are the Number 11 heads?

Drivetrain is a personal choice. The Ford 9" is the way to go in my opinion if you are looking for a strong rear end that will last and handle most all punishment. Never messed around with the OD automatics. Cliff Ruggles has a book that covers all this and I suggest you purchase it if you don't already have it. Good info in knowing what you are getting into. :thumbsup:

 

[Slow&Easy1]

Thanks for the advice. Yes they are #11 heads and I will go with the screw in rocker arms and I will look into changing the valve sizes. I will assemble the engine and everything else on the car I hope. Ive looked at different wheel/rpm calculators and such and I’m hoping the 14x7 rally II’s with 225/70/14 tires, 3.70 rear and 200-4r gives me good initial acceleration and a good highway gear - the acceleration left something to be desired as original. I am looking at the butler internals and to buy the book also
Thanks again

 

[PontiacJim]

Thanks for the advice. Yes they are #11 heads and I will go with the screw in rocker arms and I will look into changing the valve sizes. I will assemble the engine and everything else on the car I hope. Ive looked at different wheel/rpm calculators and such and I’m hoping the 14x7 rally II’s with 225/70/14 tires, 3.70 rear and 200-4r gives me good initial acceleration and a good highway gear - the acceleration left something to be desired as original. I am looking at the butler internals and to buy the book also
Thanks again

Sounds good. You can have the block notched by a machine shop, but I am pretty sure yours should have them. I included a photo of a 350CI block with the notches/scallops on the side of the bores. This is a 1970 block.

"All 350s can safely be bored 0.060-over. The most desirable blocks to look for were made from 1968 through early 1970. They may not have the correct mounting bosses needed for some later applications, but their larger cylinder-bore valve chamfers require less notching for valve clearance with big cams. Check for valve-to-bore contact by placing the valves, retained by clothespins, in the heads. Coat the potential bore-to-valve interference areas with machinist’s dye, place the head (with no gasket) on a bare block, and carefully drop the valves to establish the contact point.

Valve To Bore Contact Is Most Likely To Occur On The Exhaust Side. Grind Clearance As Needed. Maintain 0.025 Inch Clearance Between The Bottom Of The Notch And The Top Of The Piston Ring Land At Top Dead Center."

If you go bigger valves, 2.11" & 1.77", you machinist will have to open up the "throats", which he should be able to do. You will want to gasket port match the intake side of the heads. You can do this yourself after you have the heads disassembled, magnafluxed for cracks and hot tanked. You do all this kind of work before having the valves done. I used the RA IV intake gaskets and then blended the taller roof in about 1/2". YouTube is your friend if you want to get an idea of what you are doing.

If you decide to go with 1.65 rockers, you have to elongate the pushrod holes that go through the head or they will hit. However, I would stick with the factory 1.5 ratio as it puts less side loading on the rocker arm stud. Just get a cam with the lift you want to go with using the 1.5 rockers.

If you go with larger valves, I went with the Ferrea stainless steel valves. Also went with the longer RA IV valves so there won't be any issues with a high lift cam. You will need matching springs and retainers - which you want anyway going with a roller cam. Some will suggest adding hardened valve seats on the exhaust side. I don't see a need with the SS valves, but if you go high spring pressures and you have valves pounding the seat, hardened seats may be a plus. This is something to discuss with your engine builder.

I recommend buying the Pontiac Heavy Duty Parts Specs by H-O Enterprises. Several on Ebay and inexpensive enough. Has a lot of info that may be of interest or at least give you a good bit of Pontiac engine knowledge: https://www.ebay.com/itm/PONTIAC-HEAVY-DUTY-PARTS-AND-SPECIFICATIONS-MANUAL-H-O-RACING-SPECIALTIES-INC-/391930120552