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Rv motorhome build

8K views 19 replies 6 participants last post by  Dannyringo 
#1 ·
Hello:
Want to throw this out there and get ur thoughts on what I am planning on building.
1) 1978 Mobile Traveler Rv @ 18.5 ft long. GVW is 8,400# with a 4.10 rear axle. (I think real weight is about 7,000#?) Motor is a 5.7 350 4 bolt main which will be a rebuilt motor from Mabbco Enterprises out of Tyler Texas. Going with dished cast pistons w/hardened rod bolts, nothing fancy.
2)The cam is going to be the Lunati 256/262 60101Lk cam w/lifters. Heads are going to be the RHS Vortec's with 170cc 202/160 valves.
3) I think I made a mistake by buying the KMJ airgap vortec intake. After I bought, I found a couple bad reviews. 1 on the intake I just bought( to much slag) and the claim that the distributor hole was off 1/4"? So, I am hoping that this has been corrected by the company that manufactures these.
3) I am thinking of the 680cfm vacuum secondaries Quick fuel carb.
4) Head gaskets are fel pro 1003 @ .041 compression thickness.

Well, I do not know the deck height, nor do I know the cc of the top of the pistons which are dished. But I think it is safe to say it is going to be near stock values.
What can I expect on Horse power? I am after low end torque for climbing all the mountains in Arizona on the highways, as well as low end torque when I take it off road for camping...I consider this my billygoat on wheels..It can get into places that 4x4 do..Nothing fancy here folks at all.
Thanks
 
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#4 ·
Rv Motorhome build

Boatbob:
Currently this set up is getting around 8 miles a gallon. When the motor was fresher 7 years ago, I was getting almost 12mpg~! But climbing up the mountains was only 40 to 45mph. I am tired of running behind the big trucks going up mountains....
 
#5 · (Edited)
Rv Motorhome build

AP72:

Gapless rings, I will check into them. thx. Summit has a kit for my van that is a complete header muffler system...Headman headers @ 1-5/8" primaries, with mufflers, pipes and all hardware 2-1/2 pipes out of the headers.
The heads are completely setup already..Looks like the 202/160 stuff. with plates and screw-in studs.

So, how does it sound for possible Horsepower, figure 300-325? that is my target.
Just got the intake from KMJ..They are selling the Pro comp airgap intake...does not look too bad. Might need to clean up with a gasket match, though.
 
#6 ·
In a RV horsepower would never enter my mind, my only thoughts would be what torque it developed. The RHS heads are excellant, we run them. Team them up with a Quadrajet and the low end throttle response is almost as sensitive as fuel injection especially teamed up with headers and a RV cam.
 
#7 · (Edited)
DoubleVision said:
In a RV horsepower would never enter my mind, my only thoughts would be what torque it developed. The RHS heads are excellant, we run them. Team them up with a Quadrajet and the low end throttle response is almost as sensitive as fuel injection especially teamed up with headers and a RV cam.
Interesting...So, perhaps the Airgap is too much and maybe the performer would be better? My current Quadrajet for some reason only has the primaries opening; the secondaries do not work and I just do not remember if the previous owner stated he did that to save on fuel..Just do not remember...I could go with a carter though, no? what cha think...
 
#8 ·
Here is a picture of my RV...18.5 ft long GVW is rated at 8,400# It has solar, a back up generator, and ham radio equipment inside, ready to go in an emergency. Fridge, stove, oven, shower and toilet. After the motor is redone, the next thing I am looking at is 4x4 conversion! I have been looking at suburbans in the same yr range (up to 86) an it looks quite easy from what I saw of the frame mounts on the front end. I am curious if these parts could be harvested from a suburban and bolted and welded into place. I already know that I need to get the undercarrige out of mine and the burb's into mine. shock mounts and spring mounts, tranny mounts, ect....
 

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#10 ·
38 special:
Your right on the 14 bolt rear end. currently that is what I have in it. I kind of think it should have been dually rear axle, but Mobile Traveler used the 1 ton cutaway van with single rear wheels...I would have to convert over to a detroit locker, or posi rearend. I am tired of getting stuck in sand, mud and loose gravel. It sinks like the Titanic and down here in Az., there are not a lot of heavy tree's to use a winch on to pull this boat anchor out~! They had a design flaw when they installed the holding tanks in the rear. They are so low to the ground that I have destroyed them several times and recently fubared them to the point they can't be repaired anymore...So, 4x4 and a lift kit, after the new motor...Currently looking at Craig's list looking for 3/4 /1 ton 4x4 chevy truck up to 1982 for the running gear...Dana 60 with 4.10's...If nothing else, we are going to have fun doing it and learn through mistakes...Measure 4x, cut once~!
Thanks for the reply~!
 
#11 ·
Running ms1 and a tbi unit would work well in this app and is pretty cheap. Usually I would go with a standard oil pump but in your high stress application id go high vol high presure. The airgap intake will work fine. Id go with a 200 or 210 thermostat and an oil cooler too. Tbi injection will really help your fuel consumption over a quadrajet, and tuning is a breeze. The more running conditions vary the more going efi can help, I think this would qualify and very varried.
 
#12 ·
It might be too late, but if you find the right suburban/pickup you can take the entire frame and drivetrain with the BBC. The 454 will make the torque you are looking for with a few minor modifications. A later year model will net you fuel injection and a 4l80e as well. If you do it right you can sell your small block and get your frame, 4x4, and BBC and make some money.

I have a 98 2500 w/ a 454 4x4 long bed reg cab. Want me to measure the wheel base and stuff for you?
 
#14 ·
ap72 said:
Running ms1 and a tbi unit would work well in this app and is pretty cheap. Usually I would go with a standard oil pump but in your high stress application id go high vol high presure. The airgap intake will work fine. Id go with a 200 or 210 thermostat and an oil cooler too. Tbi injection will really help your fuel consumption over a quadrajet, and tuning is a breeze. The more running conditions vary the more going efi can help, I think this would qualify and very varried.
I found this ironic, because this morning, before coming here, I was just looking at the FAST efi under 600hp conversion system. I was really impressed with what I saw. Best of all, I don't need to become a rocket scientist to install it, so that might be an option. I do have a question, though. Some years ago, I had a 1 ton chevy TBI truck. I tried like hell to get better fuel mileage by going with a mild chip. The best mileage was only 10mpg. Needless to say, I got rid of it. Then I ran into this vehicle and gambled on it by trading a 1978 Jeep wagoneer straight up. The Jeep did get 12mpg. This rig almost got the same mileage, as long as I did my part. (55mph) on the freeways and best throttle on streets...Now the motor is toasted, so options are still on the table for this build..
Thanks for the idea and again, I was looking at the FAST EFI fuel injection kit this morning~!
 
#15 ·
ethn_bert said:
It might be too late, but if you find the right suburban/pickup you can take the entire frame and drivetrain with the BBC. The 454 will make the torque you are looking for with a few minor modifications. A later year model will net you fuel injection and a 4l80e as well. If you do it right you can sell your small block and get your frame, 4x4, and BBC and make some money.

I have a 98 2500 w/ a 454 4x4 long bed reg cab. Want me to measure the wheel base and stuff for you?
ethn_bert.
Wow, if you can do a measurement that would be great. I can find out how long mine is, but I would have to get over to the storage place and get the manuals out to learn the info. From what I researched, up to 86 would work under mine, but as another person just said, beware of the Dana 44, not strong enough...I am a veteran and I have been looking at the M1009 trucks the military is/was using. They are 1-1/4 ton rated with Dana 60's both front and rear with very heavy duty parts under them (detroit lockers, but w/4.56)...Only drawback is the diesel motor in them. they suck~! So, I have been looking for one within my $ range to get through Gov. auction and then sell what is left on ebay..
 
#16 ·
did not buy RHS heads

Hello:
I contacted the vendor that had the RHS heads and asked what parts were in the heads...Comp Cams parts were supposed to be in them...His reply was that they were not comp Cams parts...He gave no additional information as to what valves, springs and retainers were in them....
So, I went with the Summit Racing Vortec heads....They are made by Dart, as many know and I am really impressed with the quality of the heads....67cc chamber w/1.92 I/1.54E Now after drueling over them for about 5 min. I saw how nice the Intake ports look as well as the exhaust ports...I am really wondering if these are "sleeper" heads~! The ports have no real ridges in them like the old fuelie heads did where you had to take a dremel tool and smooth them out...Also the intake gaskets are so close, that I am not going to do anything to them, as to matching them. Both set of valves were undercut before the seat! I did not expect that, but they are..Overall, although the claim is 232 cfm on Intake and 139 on Exhaust. I have a feeling these might flow more~!
I think I got a woody~! :pimp:
 
#17 ·
PMW vortec rocker arms

I also ordered and got today PMW vortec rockerarms with the roller tip....I did some investigating on the internet and saw good reviews on them, so I took a chance on them and they look pretty good. I pulled them out of the package and really looked hard at them...The quality is there and they appear to be very heavy duty...1.52 ratio is stamped on them, so I am curious how close they are to that spec....
 
#18 ·
Dannyringo said:
I also ordered and got today PMW vortec rockerarms with the roller tip....I did some investigating on the internet and saw good reviews on them, so I took a chance on them and they look pretty good. I pulled them out of the package and really looked hard at them...The quality is there and they appear to be very heavy duty...1.52 ratio is stamped on them, so I am curious how close they are to that spec....
Name is PRW roller tip rocker arms.... :welcome:
 
#19 ·
Dannyringo said:
Here is a picture of my RV...18.5 ft long GVW is rated at 8,400# It has solar, a back up generator, and ham radio equipment inside, ready to go in an emergency. Fridge, stove, oven, shower and toilet. After the motor is redone, the next thing I am looking at is 4x4 conversion! I have been looking at suburbans in the same yr range (up to 86) an it looks quite easy from what I saw of the frame mounts on the front end. I am curious if these parts could be harvested from a suburban and bolted and welded into place. I already know that I need to get the undercarrige out of mine and the burb's into mine. shock mounts and spring mounts, tranny mounts, ect....
Thought I would do an update with all the recent research I have done...I was going to use the Lunati 60101Lk cam. But after learning about recent oil anti-wear additives, I have decided to go with a Hyd. Retro Roller Cam...

I have narrowed it down to these 2 cams:
Crower 0409 retro roller
http://www.summitracing.com/parts/CRO-00409/

And Edelbrock's 2208 retro roller:
http://www.summitracing.com/parts/EDL-2208/

For a comparison, here is the lunati flat tappet cam that is being replaced with one of the above cams:
http://www.summitracing.com/parts/LUN-60101LK/

If you were to choose between the Crower, or the Edelbrock, which one would you go with considering I am using Summit/Dart vortec heads and a Pro Comp airgap intake with 3310S Holley 750cfm carb....

http://www.summitracing.com/parts/SUM-151124/

I am not interested in different cams from other manufacturers because I plan on staying with the valve springs in these heads...Which cam is the better, or as I see it, there is not any difference, or not enuf to notice in the seat of my pants...So far, Edelbrock is the cheaper price doing a search on the internet...About $295 shipped....
 
#20 ·
Dannyringo said:
Thought I would do an update with all the recent research I have done...I was going to use the Lunati 60101Lk cam. But after learning about recent oil anti-wear additives, I have decided to go with a Hyd. Retro Roller Cam...

I have narrowed it down to these 2 cams:
Crower 0409 retro roller
http://www.summitracing.com/parts/CRO-00409/

And Edelbrock's 2208 retro roller:
http://www.summitracing.com/parts/EDL-2208/

For a comparison, here is the lunati flat tappet cam that is being replaced with one of the above cams:
http://www.summitracing.com/parts/LUN-60101LK/

If you were to choose between the Crower, or the Edelbrock, which one would you go with considering I am using Summit/Dart vortec heads and a Pro Comp airgap intake with 3310S Holley 750cfm carb....

http://www.summitracing.com/parts/SUM-151124/

I am not interested in different cams from other manufacturers because I plan on staying with the valve springs in these heads...Which cam is the better, or as I see it, there is not any difference, or not enuf to notice in the seat of my pants...So far, Edelbrock is the cheaper price doing a search on the internet...About $295 shipped....
Here are the results from a hotrod mag comparison of the optional Bowtie Vortec heads from Scoggin Dickies vs Summit/Dart vortec heads

Scoggin Dickey Dart/Summit head

TQ HP TQ HP
2,500 364 139 361 137
3,000 398 227 391 223
3,400 416 269 408 264
4,000 434 330 423 323
4,400 429 359 418 350
5,000 407 388 393 375
5,500 381 399 366 383
 
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