Mclaren aluminum blocks

A little info on the Mclaren blocks or at least the 2 I have. I had mine pressure tested and they tested fine. My plan was about a 4.00 stroke with the 4.08 bore but no can do. My blocks are cut on the main cap and web for LS1 main bearings. That gives a full 360 degree thrust which I guess they wanted for a stick car. The LS1 thrust bearing is thinner than the Gen3 so no crank is available short of a billet unit. I have the 2 Bryant cranks and Carello rods to go in the blocks but they are 2.93 stroke for 305". Have also been told these blocks are not really stout enough for boost so that is out. Might be a good street rod engine but not much for the Strip. Lucky I don't have much $$$ in them. Anyone want a cool street rod engine start, cheap?

Wonder if they are machined to use an LS crank? Lots of dimensional simularities between the two engines.

I looked and can't find any info on them.

fbs63. I never thought of that. I will have to find the bore spacing and crank throw widths and compare. Not much info on this project since it never got very far. I think someone finally realized that these engines would need a bunch of rpm and back then there was no rocker gear to do that with. They did have blocks, cranks, rods, ATI balancers and intakes. Have never seen one of the intakes.

a friend bought some old dodge nascar stuff to build---i think it was dodge p7 p8 blocks----ford cranks and toyota rods---and that was what the dodge teams were using....

fbs63, looks like Gen3 is 4.40 bore spacing and LS1 is 4.46 so I think spacing for mains would be off. Might check if I can find a LS1 crank around anyway.

Incorrect!! Gen 3's are in fact 4.46 bore space.

What was the initial intended use of the McLaren block?Road racing or??

Steff. You are correct. I got it reversed. Gen3 is 4.46 and LS1 is 4.40. My mistake.

RTSrunner. As far as I could find it was for a road race series. 305" limit.

Ls cranks are about .90 shorter in length than a G3 hemi crank.
What does the rear main seal look like? what is the main journal dia? and is the tone wheel sensor hole drilled?

Back when you had PM me about the 2 blocks, (when I was looking to build a destroked g3), I contacted one of engineers I know at Mac ,His impression was the block was designed to use the R5 cranks......I'm skeptical of that because of the difference in the rear main seal and no tone wheel attachment. He also said that Mac had Valve gear for it but sold the patterns and CNC programs. he also said there was a SB2 type Victor manifold for the project.

Yes it was designed to use in a Trans am style race series with a 5.0L limit, but when DCX fell apart the program was scrapped, Cerberus had no intention of expanding any race program.

Did you look into a piston guided build?

I've never built a piston guided engine but don't see how this would help. My problem is on the main thrust, not rod side clearance. Crank still floats and needs end play limited. Course it is possible I don't completely understand all there is in the piston guided setup. Still couldn't get a 6.1 type crank in. Am I missing something? I'm don't even see the benefit of piston guided in any engine. As I understand it the small end of the rod is floated but it has very little side to side clearance so big end width of the rod is not as important because the rod is basically located by the side play at the piston, not the crank. Am I right? Like I said I have never messed with this. Never even seen it.

As for the cranks I have they have the same dimension rear seal and flywheel mount flange. 6 bolt. They are also setup for the 4 screw tone ring.
Only difference I can see other than 48lb vs around 63lb is the rod throws are honda diam. and mains are LS diam. and #3 is LS width on the thrust. Narrow.