[TransAm 474]

Evening all, as many of you know, we have been building a 1970 YZ RA III 400 for a friend of ours, that is out of his numbers matching '70 Trans Am. It's coming along nicely, and I just thought I would share a few pictures with y'all. We built it with some good internal upgrades, and retained its numbers matching "stock appearance" on the outside. Here are some specs of the engine...

1970 YZ 400 .030" over
Zero Decked
Stock N crank
Eagle 4340 H-Beams
Icon forged dish piston 14cc
Stock #12 heads, Ferrea Stainless valves, 7/16" Studs and Polylocks, 70cc
Felpro 1016 .039" head gasket
Quench .039"
9.8-1 compression
Summit 2802 camshaft
224/234@.050 .466/.488 lift, 114° L.S.
Stock 1.5 rockers
Stock '70 Cast Iron intake
Stock 7040270 RA III Qjet Recalibrated with Cliff Ruggles parts
Stock 1112009 RA III points distributor recurved by Cliff Ruggles
RA III Exhaust manifolds, dual 2.5" exhaust
TH400 with Transgo 1-2 kit
Hughes GM25-BPO 23-2500 stall Converter
3.55 rear gears

Here are some pictures

EDIT: Not Sure How To Make Pictures Show Up Big, So You Will Have To Click On Each One...

[TransAm 474]

More pictures

[TransAm 474]

And a few more...

[shoebox1.1]

Very nice! Any dyno sessions in its future?

[PAUL K]

Looks good!

[TransAm 474]

Originally Posted by shoebox1.1

Very nice! Any dyno sessions in its future?

Thanks! This one will just get the Butt Dyno LOL

Brian

[TransAm 474]

Originally Posted by PAUL K

Looks good!

Thanks Paul!

Brian

[4dblnkldude]

Looks good! What kind of power should an engine like that make? I'm gonna do something similar to that in a couple years on a 557 block. What kind of engine in the background? Ford?

[TransAm 474]

Originally Posted by 4dblnkldude

Looks good! What kind of power should an engine like that make? I'm gonna do something similar to that in a couple years on a 557 block. What kind of engine in the background? Ford?

Thank You! I would think it should make somewhere in the neighborhood of 380-400hp easy enough, since the heads are unported. The engine in the background(on the right) is an Oldsmobile 455 we are building for my brothers '79 10th Anniversary Trans Am. The other engine in the background(on the left) is a GM 5.3 LS engine.

[Jay S]

Looking good. Your on the home stretch.

I have had a 455 Olds in our 71 Chevelle since 93’.

[TransAm 474]

Originally Posted by Jay S

Looking good. Your on the home stretch.

I have had a 455 Olds in our 71 Chevelle since 93’.

Thanks Jay! I appreciate the help along the way. Finally in the home stretch, just a few small things left. We are gonna get it pumped up, drop the points distributor back in it, and get the MSD StreetFire plugs wires cut and built for it and it will be getting close.

[Dragncar]

Originally Posted by 4dblnkldude

Looks good! What kind of power should an engine like that make? I'm gonna do something similar to that in a couple years on a 557 block. What kind of engine in the background? Ford?

A friend of mine raced a 557 400, flat tops, home ported 62s and RAIV cam. Eventually it ripped the mains out of the block. Crank actually almost came out the bottom of the block. Be careful.
11.00 flat car.

[SD455DJ]

TransAm 474,

Very nice build and I think you'll easily attain the 380 hp level. That and 450 lbft of torque too. Can't wait to hear how it runs in the TA when finished.

Dennis

[TransAm 474]

Originally Posted by SD455DJ

TransAm 474,

Very nice build and I think you'll easily attain the 380 hp level. That and 450 lbft of torque too. Can't wait to hear how it runs in the TA when finished.

Dennis

Thank You Dennis, we hope so!

Brian

[TransAm 474]

Well... We finally got this engine installed, fired up and broken in, and seems to be running great so far. It hasn't been driven yet, as the 70 Trans Am is in the middle of complete restoration. One thing I gotta say.... The 2802 Summit camshaft idles waaaayy smoother than I had expected. It has almost NO Lope at all. You can tell that it isn't stock, but I would best describe the idle as more of a "heavy" sounding idle, not really any detectable lope at all. The cam is installed about 2.5° advanced from the 109° centerline, so maybe that contributes to the mild idle, and the compression came out around 9.9-1, so I would say the compression is probably soaking alot of the camshaft up as well. The lifters we used are just the standard Hylift Johnson(Topline). We have initial set at 10°. I do believe it is going to run great though, it seems to be so far anyway. Thanks to all that helped throughout this build.

[vertigto]

Any hp/torque numbers??

Very curious...

[TransAm 474]

Originally Posted by vertigto

Any hp/torque numbers??

Very curious...

Unfortunately we don't have any dyno numbers for this engine, since it was just a restoration build with a few mild upgrades. Anyone else experiance such mild characteristics with the 2802 camshaft in a high compression 400? I mean, I've seen people say that the 2802 is borderline for a street 400. I sure dont see that at all Lol

[400 Lemans]

https://www.youtube.com/watch?v=q0RQJvn9CLw Not mine but does it sound like this one?

[John Milner]

Originally Posted by TransAm 474

Unfortunately we don't have any dyno numbers for this engine, since it was just a restoration build with a few mild upgrades. Anyone else experiance such mild characteristics with the 2802 camshaft in a high compression 400? I mean, I've seen people say that the 2802 is borderline for a street 400. I sure dont see that at all Lol

I ran one in a 10:1 400. It was installed straight up. Just a very slight lope at idle. It was a hard running engine with that cam.

[Formulajones]

Those 2802's are waaaay out on a 114 LSA, and just 224 at 50 on the intake. They won't idle anything close to radical in a 400 ci engine and by no means considered borderline. It'll have a very mild lope, not much at all really, can easily be daily driven, and wouldn't even require much of any converter if at all, and work fine with very mild rear gears.