Matt's 1970 'Trans-Am' Cuda

[Derek]

Great work as usual Matt

[Matt]

Great work and write up.......Now go clean your lathe!

I know, I know......

[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.

[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.

[Stu]

[Stu Twin]

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?

[Blue]

Just out of interest Matt, what have you been revving that to?

[Matt]

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.

[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.

[SAV@RPM]

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

[Matt]

Well it's been a while !

Winter workshop update :

Had the passenger door and front wings repainted.
The wings in particular were quite badly damaged from gravel. It sticks into the hot tyres then flies off like bullets when you go fast, putting horrible outward dents in the top surface of the wings. The painters scanned the existing paint to get a formula, and the match is absolutely unbelievable.

Engine going back in after freshen-up. Custom Mahle pistons now installed. 558HP on the Dyno.


Changing the Tremec gearbox out for a new Roltek straight-cut dog engagement 4-speed, with lightweight flywheel and clutch

Fitting proper racing brakes to the front.

Updates coming over next few weeks - first race Silverstone 18th April

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[Matt]

Can someone explain the image orientation problem and how to get round it ?

Taken on iphone. They display right-way-up on my PC , but rotate when uploaded to the forum.

Thanks

[Stu]

Yes, the photo orientation thing is annoying. The official workaround to fix the photos that I found is to open the photos in edit and then manually rotate by 90* and save it. Then go back in to edit and rotate it to the correct orientation again and save. That fixes it.

The much quicker way, I discovered, is to just screen shot the photos and use those instead. They post correctly then.

Wish I could find a way to just use the photos the way they look, but that’s all I’ve found.

Looking forward to these updates. Good to see how a track car is prepped and differs from the norm. Never considered that gravel could grenade the wings from underneath like that.

Good that you could get the paint matched! I had two different places use several different levels of scanners on mine and still couldn’t get it!

[Matt74]

The body shop has made a lovely job of those wings.
Is there anything you can do to prevent the damage from reoccurring?

[mygasser]

The body shop has made a lovely job of those wings.
Is there anything you can do to prevent the damage from reoccurring?

bed liner sprayed on the underside will protect it, maybe thicker directly in line with the 'spray' of stones. the issue is it'll add weight to a race car so the extra hp will be handy, lol
neil.