'79 440 Motorhome short block - Should I buy it?

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68droptop

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I'm wanting to convert from the worn out 318 to a BB, but funds are tight. I have the BB K-member and other BB parts (heads, blocks, trans), but nothing that's even close to running.

I just saw on Craig's List a freshly rebuilt 440 short block for $250. I called the guy, and he still has it. He said it was rebuilt (0.30 over) about a year ago. The thing is, it's a '79 motorhome motor. Evidently he had other problems with the motorhome, and that's why the motor came back out shortly after the rebuild.

Could this short block make a good temporary motor? Is there anything particularly bad (or good) about a '79 440 motorhome short block? Does anyone know if it would have a cast or steel crank? Should I buy it?

Thanks for your help and advice.

John
 
probably cast crank, see if the seller can get the casting number off the side of the block or a digital of the vibration dampener on the crank to be sure. Also what's the number and letter before the 440 stamped into the flat portion on the top right hand corner of the block. I'm pretty sure that the 440 last year of build was 1978.

Terry
 
I'm trying to get the casting number. It is likely a '78 chassis titled as a '79 motorhome.

Thanks,
John
 
I think, if it's well built, even a low compresion 440 would do well.
The use of a set of closed chambered heads will help the squeeze. The biggest performance problem area for the mid to late 70's.
 
Thanks guys! I'm going tonight to buy it. He gave me a casting number of 4006630-440-7 with a date of 4-14-78.

I have a set of '67 closed chamber heads. If this motor is a 8 to 1 compression (or less) motor, does anyone know what the ballpark ratio will be with the '67 heads?

Thanks,
John
 
Well, I bought the motor. It was 200 miles round trip to get it, but think it was worth it. The old guy seemed as honest as they come, and after I bought it and was ready to leave he told me that he spent $3K in this short block. That's seems hard to believe, but it all looks like new. Maybe he meant that he spent $3K on the whole engine...

What is the right compression ratio for a 92 pump gas BB driver? If this is a 8 to 1 motor, and the '67 heads will bring it to about 9 to 1, or slightly less, should I have the heads milled to raise it further? I see a lot of talk of 10 to 1 "pump gas" motors. Is 10 to 1 ideal and would a head mill get me there?

Also, can I be sure there is no problem running my '67 heads on a motorhome motor? I haven't had a chance to study it yet, but I understand that this motorhome block has extra water passages through the deck. I guess that means the motorhome heads have corresponding additional passages for this extra cooling? If this is the case, will running my '67 heads that don't have the extra passages cause any problems like a hotter running engine?

Thanks for your info and advice.

John
 
Just bolt your heads on, I wouldnt worry about what you read. If funds are tight, I wouldnt worry about it. The heads will attach with no bad effects.
 
The heads will work fine. If you're concerned what the ultimate Comp. ratio is you're going have to do some measureing. The heads will need to be CC'd cause they may have allready been shaved and one of the piston-rod assemblies needs to be installed to find out how far the piston is below the deck when at top dead center. The formulas used to determine the effective CR can be found in the tech section. A ratio of between 9 and 10 to 1 is what most builders chase depending on cam etc. running on pump premium.

Terry
 
Thanks guys. I'm going to get the chassis like I want it and get it good and road worthy before I pull the 318. If funds are still tight when I'm ready (if I don't win the lotery - I guess I should play...) then I think I'll just get a valve job on those '67 heads and put my Edelbrock dual plane intake on it and hopefully have a solid tourque motor driver. I appreciate the help.
 
Is it a cast or forged crank? Just curios because a friend told me all motor homes had steel cranks no matter what the year.
 
It looks to be cast. I'm embarassed to say it, but I don't really know how to tell the difference. It seems to have obvious casting marks. Is there an easy and obvious way to identify a cast crank vs. forged?
 
68droptop said:
It looks to be cast. I'm embarassed to say it, but I don't really know how to tell the difference. It seems to have obvious casting marks. Is there an easy and obvious way to identify a cast crank vs. forged?
Click to expand...

440`s equipped with cast cranks will have a specific damper. Look for a counterweight on the harmonic balancer, it may even say "use with cast crank only". The 440`s that used the "six pack rod"( and some of the HD applications did) had a similar balancer used to offset the weight of the heavy rods but were outfitted with steel cranks. Forged cranks will have the damper without the extra weight. It sounds like a good deal either way, but if you`ve got one with the steel crank ,it sounds like you did well!
 
The way I see it, if the Crafstman truck series engines can make over 700 HP on a 9.0-1 engine, theres no reason, except your budget, that you can not make good power with that 9.0-1 ratio 440.
Ok ok ok, so the truck engines have a zillion dollor budget and W-7-8-9 10 what ever heads with custom porting and big rollers, but I think you get the point.
 
The crank number is 4027175-5 and the damper says "Use With Cast Crank Only", so I guess that settles that. Oh well, If I don't try to do anything silly with this motor I should be okay. Several of the rod caps look like they have been machined so that some are flat and some are more rounded. Could this mean that the motor has been balanced or would this be an original factory thing?

Thanks,
 
68droptop said:
The crank number is 4027175-5 and the damper says "Use With Cast Crank Only", so I guess that settles that. Oh well, If I don't try to do anything silly with this motor I should be okay. Several of the rod caps look like they have been machined so that some are flat and some are more rounded. Could this mean that the motor has been balanced or would this be an original factory thing?

Thanks,
Click to expand...

Yep, that settles it, but don't be to worried about what that crank can take. I'd say 450 hp is a safe bet but others may disagree. I can't picture the rod cap machining, could you post a digital maybe.
 
You can go father than 500 and be safe with a cast crank.
 
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