stelldo
Member
Anyone know if anyone has done it? This would be a cheap build. Use stock roatating assembly. New rings bearings hone cylinders etc... Add blower cam and 906 heads. I have the blower and manifold and supporting parts.
RV 440+ 6-71 blower
- Thread starter stelldo
- Start date
court9155
Well-Known Member
Run it on E85 and limit the RPM and boost and you may get away with it....maybe put a new harmonic balancer on it cuz Im sure its 20-30 years old.
Dan
Dan
RustyRatRod
Well-Known Member
Yeah it'll work for a while. Expect to crack a piston on down the road.
stelldo
Member
Yeah i was thinking limit rpm and boost it would live for a while. I am on limited budget like everyone. wow factor and fun for a while anyway. You think 5-600hp is a reasonable expectation? I am assuming rv motors have cast cranks, so that would be externally balanced correct?
Sweet5ltr
Well-Known Member
I have a 1973 440HD engine that was RV/POLICE issue, pulled from a Highway Patrol car. Forged steel crank and "Six Pack" rods. Also was Internally balanced. I believe in 74'+ they went to cast cranks. Have you actually priced out everything necessary to run the 6-71 blower? I believe it is really not that cost effective. It would look much better sitting on top of a pair of aluminum heads, even stealths if that is all you can afford.
HT413
Semi Pro Bowler
I believe that most RV and industrial motors had forged cranks, though there were some that had cast.
stelldo
Member
I have a lead on a motor for $250. I don't know the year yet. I will have to look at it to find out I am sure. You know the story "ran good when pulled just scrapping out the rv". I have fresh 906 heads ready to bolt on. I have the blower, manifold, pulleys, belts carbs etc... All set up for a 440. I basically have everthing except a short block.
Sweet5ltr
Well-Known Member
yes, they ran a paxton kit. Made in the low 400 range on the Dyno with stock cylinder heads. Placed a 6-71 blower on an Indy BBM and made 800..
RustyRatRod
Well-Known Member
If your compression is low enough you may can get by for a while. A lot of the later big blocks had the compression advertised at like 8.5 but in reality it blueprinted well into the 7s because of the infamous lousy deck heights of the Chrysler engines. They are notorious for having tall deck heights and that would certainly be in your favor. I would say if you could blueprint compression to say 7.9 or lower and watch the spark advance you'll be ok.
PurpleBeeper
Well-Known Member
If you are looking to go CHEAP..... then I'd suggest some stronger rod bolts, forged blower pistons/good rings for sure, best blower head gaskets you can find (steel shim type???) and "maybe" some cylinder head studs.
And I agree with the other posts.... keep the boost down, the octane up and don't advance the timing too far.
Also, if you have one of the motor home blocks + heads that have the cooling passages around the spark plugs that would be a bonus for a blower motor. And Sweet is right.... my 73 motor home block came with the "six pack" rods and a forged crank.
hemi duster
Active Member
Im building the same type of motor at the moment,,,, I have a 1976 block,,, cast crank is coming out,,,, These cast cranks are only really good up to 600 hp,,, and like every one else,,, your going to want to lean on the motor,,,, I know I would.. Just a matter of time until it grenades on you... Im trying to keep in mind that once it does it will cost you more money,,,,
get a steel crank, it in, then port your 906's , try to put a descent cam, lifters set up,, not too wild, like in the 636 lift range or the high 5's and run it ,,, at least then you can spin it and lean on it with some security...
get a steel crank, it in, then port your 906's , try to put a descent cam, lifters set up,, not too wild, like in the 636 lift range or the high 5's and run it ,,, at least then you can spin it and lean on it with some security...
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