Matt's 1970 'Trans-Am' Cuda

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Derek
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Re: Matt's 1970 'Trans-Am' Cuda

Post by Derek »

Great work as usual Matt =D>
Are we there yet dad ..... 10 to the gallon but worth it.

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Matt
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Re: Matt's 1970 'Trans-Am' Cuda

Post by Matt »

Kev wrote: Mon Nov 28, 22 11:39 pm Great work and write up.......Now go clean your lathe! [-X

I know, I know......
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Matt
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Re: Matt's 1970 'Trans-Am' Cuda

Post by Matt »

I was going to strip and rebuild the engine properly over the winter , but it turns out the engine had other plans.

Donington , September.

Sudden bad vibration whilst racing, quickly followed by a very big bang. Coasted to a stop, fortunately out of the way.

Looks like the crank finally let go. It's had a good innings, in fairness. A forged crank was specced when building the engine, but for some reason ( I have long ago forgotten any explanation for this - probably availability) I ordered a cast one instead.

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Well it was the last race of the season, so probably the best time for this to happen.


I had a spare 360 block that I picked up a couple years ago in case I needed it. Stroker cranks, however, (either Eagle or Scat) not showing in stock on Summit etc .

Kev Borland who races with me said to try Hausers, and it turns out Geof can source an Eagle crank. Whilst on the phone to Geof about the crank I said - 'Geof, can you just build me the whole engine?' , and that is now what's happening.


Now that I've got a couple of years racing under my belt, and I don't appear to be a severe hazard either to myself or others, I think I'm ready for some more horsepower.

Geof suggests that with a custom cam grind, improved valvetrain, and better breathing , the compression can be raised quite a bit. All this will add up to a fair amount more horsepower (quite how much I'm not going to guess at until the dyno results are in)

The main hold-up will be the Mahle pistons which are looking like about 12 weeks at the moment, although most of the other work can be done in the meantime. Hopefully back in the car late March 2023 in time for the season.


The new engine will rev higher and should make its peak power at higher rpm , so a change of axle ratio is on the cards, also better brakes.
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Pete
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Re: Matt's 1970 'Trans-Am' Cuda

Post by Pete »

That is what is known as a "Proper Job"....

Good luck with the new build and great to see you today.

All the best. Pete.
Pete Wiseman; Cambridge.

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Stu
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Re: Matt's 1970 'Trans-Am' Cuda

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:atthemovies:
24 hours in a day, 24 beers in a case. Coincidence? I think not…

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Stu Twin
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Re: Matt's 1970 'Trans-Am' Cuda

Post by Stu Twin »

Matt wrote: Tue Nov 29, 22 11:07 pm
The new engine will rev higher and should make its peak power at higher rpm , so a change of axle ratio is on the cards, also better brakes.
Hmm, things seem to be snowballing!

See what I did there?

:D
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Blue
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Re: Matt's 1970 'Trans-Am' Cuda

Post by Blue »

Just out of interest Matt, what have you been revving that to?
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Matt
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Re: Matt's 1970 'Trans-Am' Cuda

Post by Matt »

Blue wrote: Thu Dec 01, 22 4:59 pm Just out of interest Matt, what have you been revving that to?
Peak Torque is at 4300rpm and peak HP at 5400rpm

I think I set the shift light to 5,700 rpm. The car feels to me like it normally wants to change gear somewhere below this point, and I felt I should err on the side of caution

It's been revved beyond this occasionally , and there have also been two 'select 3rd instead of 5th' moments, which were probably quite a significant over-rev, but that was a long time ago.
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Re: Matt's 1970 'Trans-Am' Cuda

Post by Blue »

Interesting, my 408 also has a cast crank and I'm turning it a fair bit higher than that but I guess circuit racing is a much harsher environment.
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Re: Matt's 1970 'Trans-Am' Cuda

Post by SAV@RPM »

I have only ever run forged cranks, internally balanced for a circuit car
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