Hi, my name is Steve and I'm a Barth junkie...

So why would I take out a 454 that is running well and replace it with a new one?

The OEM engine is running well with the new crankshaft and bearings. 40-60 psi oil pressure, good compression, uses 1 qt in 12-1500 miles. 110k total miles.

Problem is, I have over 25,000 miles in the last 3 years. In another few years the engine will be ready for rebuild. Question is, will I still be able to do it by then?

Meanwhile, the old 454 is only rated for 240hp. Low 7.9 to 1 compression limits power for hills and trailers.

Even if I did rebuild the old engine (I could) it would need pistons and boring, valve job, etc. It would still have 2 bolt mains and old style split rear main seal...

Meanwhile, I am working on wheel wells, getting ready to paint (someday) I also plan to replace windshields before I paint. While the windshields are out is a perfect time to change engines...

If I got a new crate motor… (GM part #12568774) I could drop it right back in as soon as the old one is out, not weeks later after machine shop, etc..
It would have all forged parts, 8.75 to 1 compression, 4 bolt mains, one piece seal, roller cam, 425 hp with 500 lb/ft torque!

So, what would you do?





(At least this way I'll have a good engine left to revive one of Mary Ray's fleet.)

My name is Steve, I'm a Barth junkie.

to be continued...

OK Stevey Baby Go for it. Cant wait for the pictures.............................

quote:

So, what would you do?

Seek counseling.

I can't thank my fellow Barther's enough for all the gifts that I have received. Each one is a treasured gift that they could have sold or traded and they chose to give these items to me. That is true love!!!!!

quote:

Originally posted by Steve VW:

It would have all forged parts, 8.75 to 1 compression, 4 bolt mains, one piece seal, roller cam, 425 hp with 500 lb/ft torque!

So, what would you do?



My name is Steve, I'm a Barth junkie.

The HT502 has a more usable ports, cam and power band for a heavy motor home. The 454HO would benefit from a Gear Vendors to get the most out of its power band.

It will be interesting to compare power bands. Looking at the dyno curves there is not much difference from 2-3,000 rpm. The 502 has smaller valves and shorter duration cam, potentially better torque (not to mention more displacement.) I suspect the torque gain in the 502 has much to do with displacement.

The 454 comes complete with intake manifold and water pump It is several hundred cheaper, has square ports which match the square Thorley headers, rather than the later style oval ports on the 502.

The 454HO will put out more hp at 3000 rpm than the old motor did wide open. I suspect an overdrive will be desirable, I can't use one now with the lower output engine. Without the overdrive, the extra displacement on the 502 is potentially wasted with higher rpms, with it the 454 it should be adequate. We shall see!

454 dyno


502 dyno


Compare to stock 454:

quote:

Hi, my name is Steve and I'm a Barth junkie...

The first stage of recovery is to admit you have a problem.

That is one heck of a beautiful motor you got sitting there Steve.

So have you established a time line for this project?

Thinking about mid summer for the transplant. I have pass side windshield, driver side is on order. After Milford and Canada fishing, I'll try to get to it then.

quote:

Originally posted by Steve VW:
It will be interesting to compare power bands. Looking at the dyno curves there is not much difference from 2-3,000 rpm. The 502 has smaller valves and shorter duration cam, potentially better torque (not to mention more displacement.) I suspect the torque gain in the 502 has much to do with displacement.

And a longer crank arm.

quote:

The 454 comes with intake manifold and water pump and is cheaper to boot, has square ports which match the square Thorley headers, rather than the later style oval ports on the 502.

Square and oval ports refer to the intake ports. The exhaust ports are pretty much the same. On stock Chevy heads, the square ports do not show an advantage until you get over 5000 RPM. My ski boat 502 has oval port aluminum Bowtie heads ported by AFR, and they produce more power than the square port heads they replaced. I can state this unequivocally, because a jet pump is like a water dyno. And the smaller, higher velocity ports provide much better part throttle running and fuel economy. It would barely idle with the square port heads and manifold. Of course, part of that was a rasty cam but I mention it just to illustrate the advantages of higher velocity intake ports. The higher velocity also fills the cylinder with a more turbulent mixture that allows about a half point more compression. However, playing with the squish can do that, as well.

quote:

Without the overdrive, the extra displacement on the 502 is potentially wasted with higher rpms

Yes. The ht502 is a hauler, not a racer. If I were building a heavy hot rod or (non-towing) pickup, I would not use it.

My opinions here are colored by the fact that we tow a heavy 4WD or boat up some steep grades, so your needs might be a little different.

quote:

Originally posted by bill h:

And a longer crank arm.

??? The 454 and 502 have the same 4.00 stroke... Should be same crank arm? 502 has bigger bore...

Thanks for explaining the intake port shapes. That could have been an issue. Since the 502 does not come with an intake manifold, I'm not sure my OEM 1986 454 manifold would fit and have same port type.

My TBI fuel injection adapter plate is set up to bolt onto a carb type manifold anyway, so the new 454 manifold is good. I didn't want to have to buy/swap too many additional parts. (I obviously would have needed advice to buy the correct manifold.)

quote:

Originally posted by Steve VW:

quote:

Originally posted by bill h:

And a longer crank arm.

??? The 454 and 502 have the same 4.00 stroke... Should be same crank arm? 502 has bigger bore...

OOPS! Shoulda verified before posting from memory.

Awesome! Maybe add a blower in the fall?

quote:

Originally posted by Tonka:
Awesome! Maybe add a blower in the fall?

You bet! Maybe some wheelie bars?

Nothing like a few pictures of a hot rod motor to get this site going again!

Too bad it won't be ready for Milford. There's always next time!

quote:

Originally posted by Steve VW:


You bet! Maybe some wheelie bars?

The 502 can twist the axle housing, so traction masters or a torque arm would be a good idea if you get into rough stuff offroading.

I was rocking to get out of a bad spot, and the housing rotated enough to cause an air bag to come apart.

Steve, I think it sounds like way too much work.

It would be much easier on you if you just shipped that crate down here to Crystal River