Slow build 71 Scamp 440

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Can anyone give me some insight into my rear end? Question is……. The flex line from the body to rear end the same across the 7 1/4 and 8 3/4? Looking for no surprises. Need this baby mobile asap after the swap.
 
Ok long time no update! Ok so the engine is on the sideline with my head in the fog about next steps. But in the meantime the car was sent in to get the rear end swapped out. I built it over last winter and I was going to put it in myself but my shoulder said no for the time being. I should have it back next week. Slant six, 904 with 8 3/4 SG 3:55. Lol. Think it will spin. Lol
 
Before photos. 7 1/4 Those HD springs and KB’s look fine.

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Got the car back today. Everything went great. So the car is setup for some horsepower. New tires all around. What a difference in ride now. When it goes in for paint I’ll enquire about a mini tub and some frame connectors but that’s down the road. But for now we cruise and sort out my engine build problems.

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Ok we have noise! Not nearly as bad a 7 1/4 with the shot pinion bearing. But this sounds bad especially over 75kph. Two different noises. I’ll try to describe them the best I can. Noise one happens when I let off the gas and just before the engine starts slowing the car down. It’s like a hum/vibration. Power no noise, engine starts slowing down without gas no noise. Just that transition between power and no power. Pinion pre-load?
Next noise is at speed. Vibration hum in and out in and out. Drive shaft not balanced?

Maybe it’s the driveshaft causing all the problems. I don’t think they balanced the shaft as I supplied the shaft from a purchase made on here. Maybe it needs to be done.

Pattern on gears when done was perfect.
New and balanced tires.
New rear end 3:55 S/G
904 transmission (no change)
All rear end components new.
 
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Well that explains it. I sent a spare shaft down to the shop. The shaft was for a 727 8.75. So it’s obviously two short and they used it. So this would explain the racket underneath at speed. So I’ll take the car over to them again next week and use the “roll on lift” and do a remeasure and have the original 904 7.25 shaft cut and balanced. We learning folks.

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Ok a little better but noise persists. I only had it up to 70kph and it started. I didn’t have time to take it on the highway yet. Try that Monday. Brand new shaft as they messed up my slant shaft. They cut the wrong end off and it had the rubber sleeve in it and I guess they didn’t want to deal with it. So all new rear, u-joints and shaft and we still have something going on. To what extent we find out Monday with a trip up to 100Kph. Not going to mess with it as Moparfest is this coming weekend. It’s good enough to get me there and back.

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that looks better, i'd still have made it longer though. if there was a normal seal and not the one with the long dust 'cover' bit it'd be clearer. looks like there's a polished mark on the yoke where it used to be further in and the seal touched/rubbed on it, but that's not even in the dust cover. it'll be better yes, but not ideal.
neil.
 
She was marking her territory pretty good before. It stopped now that we pulled it out a bit. It was a decent grove where the seal rode. I agree it’s a bit two short still. 51 3/4 is what we have centre to centre ( /6 - 904 - 8 3/4 ) This shaft will be cut down again once we get the 440/727 in there.
 
Ok an update on the engine fiasco. I purchased a block out of Quebec. It’s a date code 71 so that’s nice to match the year with the car. I know it don’t meant poop! It was a standard bore. Just got word back that it’s will be good to go to .030. It’s been sonic tested and shows good. So it will be line bored, zero decked, set up for molly rings, new frost plugs, cam bearings and 10.1 compression.

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Engine fiasco background: Engine was bored to .060 with all the bells and whistles. I was told when I picked it up it was at .030. So I had all my rotating assembly balanced and pistons purchased were .030. So when I put it together you could imagine my shock.
 
Skeeter007 said:
Ok an update on the engine fiasco. I purchased a block out of Quebec. It’s a date code 71 so that’s nice to match the year with the car. I know it don’t meant poop! It was a standard bore. Just got word back that it’s will be good to go to .030. It’s been sonic tested and shows good. So it will be line bored, zero decked, set up for molly rings, new frost plugs, cam bearings and 10.1 compression.

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Great, glad you got a good starting point.
 
Skeeter007 said:
Well that explains it. I sent a spare shaft down to the shop. The shaft was for a 727 8.75. So it’s obviously two short and they used it. So this would explain the racket underneath at speed. So I’ll take the car over to them again next week and use the “roll on lift” and do a remeasure and have the original 904 7.25 shaft cut and balanced. We learning folks.

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Holy ****, I can't believe a shop actually did that.
 
Ok fresh back for Carlisle’s and the fire is lit again……. So here’s where we’re at.

1971 block acquired, cleaned and all the goodies done to it. Bored to .030 over. Crank, pistons fitted. 10 in the hole

Cam installed. ARP head bolts grabbed from Mancini’s at Carlisle.

Head gaskets ordered.

Up next, grab all the remaining gaskets.

Then ask a ton of questions. lol

Speaking of Carlisle’s, amazing time. Good people, great conversations and made some new friends. Looking forward to next year. .
 
Can some one help me out with some compression calculations. I have tried the summit calculator and I don’t think I’m doing it right and to be honest it’s not my bag.
Numbers I have and may not be correct.
Bore .030 over. 4.35
Pistons 10 in the hole
Stroke 3.75 ?
Cylinder head (sidewinder bowl blend) 84cc
Head gasket ?? .075 or .050 or?
Pistons KB 237 .030 link to info
CHRYSLER KB KB237.030 KB Performance Pistons | Summit Racing

This is a pivotal point in the build as all the hard surfaces are done and the only thing left to control any of CR is head gasket thickness.

Any thoughts or concerns?
 
Skeeter007 said:
Can some one help me out with some compression calculations. I have tried the summit calculator and I don’t think I’m doing it right and to be honest it’s not my bag.
Numbers I have and may not be correct.
Bore .030 over. 4.35
Pistons 10 in the hole
Stroke 3.75 ?
Cylinder head (sidewinder bowl blend) 84cc
Head gasket ?? .075 or .050 or?
Pistons KB 237 .030 link to info
CHRYSLER KB KB237.030 KB Performance Pistons | Summit Racing

This is a pivotal point in the build as all the hard surfaces are done and the only thing left to control any of CR is head gasket thickness.

Any thoughts or concerns?
Click to expand...
9.48:1 with the .050 the gasket.
I would use a .039 gasket to get the compression up , you can afford to with aluminum heads
If you already have those 2 head gaskets sizes then use the thinner
 
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