1973 2.4L Engine Options

[hockenheimr]

Hey Pelicans !

So, I picked up a 1973 Chassis a few months ago … that’s a whole other topic but I’m debating on colours and a few other things.

My focus right now is what to do with the engine and I don’t see too many posts on engine options for a 1973 Mag case.

Like how far can I push the displacement, how far can I push the rev limiter if I go all out on internals, what’s the best options for heads.

What would the ideal engine look like ? Or do you just go to a 3.6L?

Thanks for any help! Cheers!

[Uwon]

I’m in the same situation with a ‘73 2.4S. Initial thought is to go to 2.7 with the existing MFI but have no idea on the cam. Strictly a street tourism motor.
I’ll be following this thread with great interest.
Cheers,
Johan

[dwa917]

Just my 2 cents... I've no doubt you will get a lot of responses from more knowledgeable folks... This is on how far can you go on displacement and rev limits...

If it is a .7R case, then it is easy to go to 2.7 - that is basically what the RS case was, and the 2.7 CIS engines through 1977... When I was racing in SoCal in the 90s, my understanding of the limit for a 7R mag case was 2.9, ANDIAL used to sell the pistons and cylinders then. Not sure if you can get those anymore or someone else makes them available... That was mainly to fit SCCA regs for GT2 class racing...

With the stock 6 bolt crankshaft, 7500 RPM is probably the limit, and not all the time, as high(er) revs tend to loosen the flywheel bolts due to harmonic resonance in the crankshaft...

Look forward to seeing what you decide on engine and colour...

[hockenheimr]

Yea it’s a .7R case … just bought it on here.

I’m think why not go with a 996 gt3 crank and oil pump … what’s stopping me from getting 8k RPM out of it?

Suspension I’m thinking going full Elephant racing package.

[356RS]

Originally Posted by hockenheimr

Yea it’s a .7R case … just bought it on here.

I’m think why not go with a 996 gt3 crank and oil pump … what’s stopping me from getting 8k RPM out of it?

Suspension I’m thinking going full Elephant racing package.

With the 7R mag case you are stuck with the 6 bolt cranks. 66mm or 70.4mm stroke. All later cranks, 3.0 SC and up have the larger #1 bearing bore in the case and the 9 bolt cranks.

[PeteKz]

A well-built 2.7 engine is a great combination with a light car. If 200-ish HP isn't enough for you, then start with a 3.0, 3.2, or 3.6 core or fully built engine. If you are buying all the parts for your engine one part at a time, it will empty your wallet. Better to buy a complete engine, either ready to install, or to rebuild.

[hockenheimr]

Originally Posted by 356RS

With the 7R mag case you are stuck with the 6 bolt cranks. 66mm or 70.4mm stroke. All later cranks, 3.0 SC and up have the larger #1 bearing bore in the case and the 9 bolt cranks.

This is great to know… I know nothing about anything before the 964.

This is a learning experience.

[Bill Verburg]

Originally Posted by hockenheimr

Hey Pelicans !

So, I picked up a 1973 Chassis a few months ago … that’s a whole other topic but I’m debating on colours and a few other things.

My focus right now is what to do with the engine and I don’t see too many posts on engine options for a 1973 Mag case.

Like how far can I push the displacement, how far can I push the rev limiter if I go all out on internals, what’s the best options for heads.

What would the ideal engine look like ? Or do you just go to a 3.6L?

Thanks for any help! Cheers!

For a street car you need to consider idle and low speed operation
a 2.4S is a peaky beast that wants to rev for the most satisfaction, is traffic not so much fun

2.4S which i the same except for displacement as a much more tractable package

2.8RSR is a 2.4S on steroids

here are some of the engines that you could use


2.7RS would be great but 3.0 w/ S a]cams and EFI would be comparable to the SC/RS and seems a nice compromise. These ca easily be built to rev to 8K, bt don't need it

while a 993 3.6 vram is the most fun it's also the most expensive to get and install

[targa72e]

Here is a recent thread I posted comparing several early 2.4-2.7 engine configurations.

dyno summary and testing on early 2.4L & 2.5L

Keep in mind that how much power the transmission can live with can be a limiting factor. 73 had 915 so can handle more power than earlier cars with 901.

john