I used the 303Y-C.
https://www.barthmobile.com/eve...1087061/m/1733908187

Here is the factory link. $649 free shipping

http://www.dougthorley.com/prod-34.htm

Summit has them, too. $675 Free shipping but ships from the factory also.

http://www.summitracing.com/parts/dte-303y-s-c

I got mine straight from the factory.

Thanks once again Steve .
I will call the thorley factory tomorrow . I tried to order on there website but it won't let me finish the process for some reason .
Also , if anyone is thinking about ordering thorley headers it states on there website to use promo code DT for the best price . I was shocked to find out that took OFF 10% , to bring the price to $584.10 . That saved me almost $100 compared to summit's price.
Thanks, Bob

UPDATE

I finally got everything done & was ready to start the new 454 ho for the first time .

Used the oil priming tool , put the distributor in & set timing to about 6-8 before tdc .

I usually turn the key 1 click & turn switch on dash for the inline electric fuel pump . NO sound from pump . OK , go out check for 12 v at pump . Got 12 v . Fuel pump must of picked up some gunk when used to drain tank of old gas . no filter in front of fuel pump.

I read online about cheap fuel pumps & don't want to replace again with a cheap mr. gasket pump that is on the coach now .

Is the carter P4070 a good replacement pump ?

What fuel pump does everyone else have, along with the mechanical pump (NEW) mounted on the 454 for vaporlock ?

If i use P4070 fuel pump do i need a pressure regulator with it ? (Already 1 there after mr. gasket fuel pump, but i can loose 2 more connections in fuel run.)

What is a good inline filter to put before the fuel pump ?

Thanks again everyone for your help. Bob

Carter pump would be good choice IMHO. Should not need a separate regulator with that pump, pressure is about right for the QJet carb. They are very reliable. I had one before I switched to the fuel injection system.

Filters in the inlets are a good idea. My 87 had the wretched in tank pumps and sock screens, inaccesible for service. I had lots of fuel related problems with them.

I removed the tank junk, put these in for each tank.

http://www.summitracing.com/parts/sum-g1507/overview/

see here: https://www.barthmobile.com/eve...1087061/m/9023985387

I am now using a higher pressure frame mounted pump with the fuel injection system, so I retired the engine pump long ago.

Thanks Steve
I just got home from summit. About 1 hour drive from my home, but saves me 2 days waiting on shipping . I'm Happy to see you recommend the fuel pump P4070 ,that's the pump i purchased . I also picked up summit G1508 filter assembly & 2 replacement filters . Looks like the filter you used but different part # . Hopefully if my bad back holds out, the NEW 454 ho will come to life tomorrow .
Also, My 86 Barth doesn't have a fuel pump in the tank. Thanks again Steve , Bob

Let us know how the HO works out. should be almost frisky in your 25 ft. Cool.

I got the fuel pump & filter all hooked up .
Went to put gas into the tank from my gas can & noticed gas was leaking from the filler hose . Always something .

Went and bought the new filler hose, but bad back will not let me do much more today .
Hopefully over the weekend i will get this project completed .

Thanks again to ALL who helped , Bob

I Got the new fuel filler hose on saturday.
Put about 5 gallons of gas in the tank. No leaks.
Turned key 1 click & flipped switch on dash for inline fuel pump (NEW). Pump works great, we have gas flowing .
Proceeded to turn engine over , to fill quadrajet carb . In about 30 seconds the NEW 454 HO fired up.
I let the engine come up to temp & ran in driveway about 15 minutes at different rpm's .
I will top off all fluids today & look everything over once again . I don't have a timing light , so will have to wait till wednesday for friend with light .
Can't wait to get the coach back on the road & test out the new engine .

Thanks again , Bob

Bravo!

I think you will be very happy with that engine. Hopefully no surprises are left hiding. Keep us posted.

Update ,

I finally got the timing set on the new 454 HO engine last week .
Went for a ride in the Barth to get it inspected to be legal in PA . I left the garage with new inspection sticker smiling from ear to ear.
The 454 HO ran great. I will change the oil tomorrow & clock some more miles to break the engine in.

Thanks again for ALL the help , Bob

Good morning;

There was an interesting comment earlier about the Doug Thorley headers being the only ones that fit the GMC P37 motor home chassis with the Chevy 454 engine. One other person did speak of a Hedman header that might be available.

The Gale Banks Engineering 49052 PowerPack Kit is also the one intended for use with the dual air pump carburated 454 engine from about 1984 through 1993 before they went to the EFI TBI system. There were three (3) versions of this PowerPack kit starting with the one for the earlier single air pump 454 carb engine, the 49052 kit for the dual air pump 454 carb engine like mine, and then the one for the later 454 EFI TBI engine.

I have the Gale Banks Engineering 49052 PowerPack Kit which uses the GBE 52220 and GBE 52221 Left and Right Stainless Steel Headers. While the GBE salesman David Novelo at Gale Banks Engineering did say to me that I may have bought the last 49052 complete kit that they had in stock, most of the parts that they used to make up that kit are still available, and that does include the GBE 52220 and 52221 headers.

And, while the original GBE PowerPack Kit is just a single tailpipe design following the muffler and going out the left side in front of the left driving dual wheels, it is possible to convert that kit into a true full dual exhaust system, and that is what I am doing with mine. This dual exhaust conversion is made up from a collection of GBE stock parts, and three (3) custom made pieces to provide a cross-over pipe at the front of the GBE DynaFlow mufflers.

I will admit that it has not been cheap, and I do not really know if this will provide any improvements in power or fuel economy, but it is a fun project. The next step will be to see if the Borla 400115 Stainless Steel Mufflers added to it will make it any quieter. At least I can say that I do have a truly unique motor home RV with a custom exhaust system that clearly will last longer than the life expectancy of the RV. There are a few other "non-stock" bits and pieces on it that did not come from the GM Saint Louis assembly plant either.

I just wanted to point out that there are other options besides the Doug Thorley and Headman headers for the General Motors Corporation P37 motor home chassis with the Chevy 454 engine in it.

Enjoy;

Ralph
Latte Land, Washington

I do not know what brand headers were on my '77 but they fried a few starters.

Good morning, Dick Dubbs;

Yes, sir. There are a couple of different heat shields available to help reduce the heat radiated from the header downpipes over into the starter. There is also one commonly available for the standard length oil filter on the other side of the engine. I have one of those, but I am now using one of the "two quart" or "double length" oil filters on the Chevy 454 on the left side. For that, I made up a plain plate thin sheet metal heat shield held on to the longer oil filter with three sort-of-"U"-shaped straps with slots on the ends near the oil filter body for the stainless steel band clamps to hold the heat shield in place on the oil filter. It is better than the old single quart oil filter heat shield, because there is better air flow past the oil filter and there is more air to remove heat from the oil filter body. That metal plate also helps keep more of the header downpipe heat off the side of the engine.

From the experience last Summer with the loss of the engine in the 108º F. heat in Eastern Oregon and Washington, I am a little more aggressive in providing ways to get rid of engine and transmission heat from my Chevy 454 engine. There is also additional sheet metal paneling on top of the frame extension up front to keep the air from the front flowing back to and through the radiator instead of dumping out toward the ground between the frame extension cross rails. That also blocks the slot between the front of the radiator and the back of the air conditioner condenser where the engine fan had drawn up from below all the straw, wheat chaff, small leaves, seeds, a few feathers, and other things that had coated the front of the heat dissipating core of the cooling system radiator. That was the real reason why my Chevy 454 always seemed to run hot -- it was.

It was not until the air conditioner condenser had been unbolted and tilted forward that all the things covering the front of the radiator core could be seen. At least now I know why it did it, and things have been done to not allow that to happen again.

Enjoy;

Ralph
Latte Land, Washington

I think any header kit that will fit a GM truck of the same vintage with a BB will work on a P30 chassis. I replaced mine years ago with a cheap $90 set off ebay. I tighten them down annually but never had a problem. Maybe one day, when this set fails I will step up to Thorleys.