Technical V8/powerglide/torquetube

Swapping a V8 into a pre 1955 Chevrolet car usually requires more than just a transmission change and rear axle change to open drive. It also take trimming the pieces that support the firewall from the frame in most cases I have seen.
If I wanted a newer engine in that car I would go with a later model =235 Chevy six or possibly do an engine and transmission plus rear axle swap for a readily available in Norway straight six with matching transmission. Hotrodding is hot rodding and one doesn't have to be stuck with an American engine for it to be a hot rod or improved performance car with a stronger and reliable engine. There are probably common mid size gas powered trucks running around Norway with straight sixes that would fit without an issue. That is just a thought for having a reliable and easy to care for car where you are.

 

Theres a huge hotrod/Kustom culture here. And plenty us cars. But the trick is to find the right parts. As i said, i have a couple of 235 engines already, but the rebuild cost is high. Thats why i tought about a more reliable v8 swap. Probably more fuel efficient also. Gas prices here is super high now. About 3 dollars pr litre.

 

307 / powerglide, convert the car to open driveline.
307 - had low compression and heads were weak performers, compared to other small block chevy's. Drive it as is, or upgrade it later.

 

https://www.trifive.com/threads/powerglide-v8-vs-i6.116011/

 

307 has a large journal crankshaft. The only way to make a 283 would be to swap in a Z 28 302 crank or aftermarket one. The 307 had thin wall casting cylinder heads and tended to crack also I'm pretty sure they couldn't be bored to 4.00 inches. But with the choices you have mentioned, the 307,aluminum powerglide and open drive rear is the better choice. I made a 327 once with a 350 block and a 307 crank.

 

What’s your confidence level in the 307/PG you found?
I realize that where you’re at you can’t just Wade through the several CL/FB ads for SBCs and transmissions.
FWIW, I had a 307 in a ‘68 Biscayne, had a 3sp auto though, assume a TH350. Not a hotrod but was a good running combo. Never any issues with the engine. If the one you’re looking at is a good runner and since you probably don’t have the choices available to you that we have, I’d go that route over a 235/PG.

 

The Axle in this package that i found has 3.71 gears. Is that ok with the powerglide or will that be too much rpms cruising down the highway?

 

Hi gear/ direct / drive is 1-1. Depending in tire size which can change it a bit, probably be in the 3k rpm around 60 MPH. Many online rpm calculators you can plug the numbers in to.

 

I checked a calculator and you hit it spot on. I feel Thats a bit stressed.

 

Chevy 55-64 rear’s did have not 3:08’s in the beginning years. V8 Powerglide cars got 3:36’s.

I can say switching to 3:36’s from 3:73’s made frwy driving much better.

 

Do that.

 

With the correct bearing adapter or bearings a 283 crank fits a large journal block.
Lot of 302's been built on a 350 block this way using a 283 crank .

Same crank will go into a 307 block also . No idea why you would but it's doable . Bearings or adapters not cheap but it's doable.

A 307 will go .060" over and get you close to a 327 ( 317") with the correct piston your only down a few HP down from a true 327 .
I built a bunch back in the day with forged .060 327 pistons .
Have one in a car now .

With 350 blocks still easy to find there is no real reason to build a 307 if it needs to be bored .

I have done a bunch of 307 cranks in a 350 to get a 327 .

 

I don’t think (or know) he’s getting it from a ‘55-64, as the engine is a 307 with Al PG. My thought is he knows someone with a collection of different stuff-which is fine. Also assume it would be a 3.73:1 rear as well if GM.

 

I had a stock 3:70 gear behind my 261 it had great throttle response it turned about 2500-3000 R.P.M. without an issue
and it got respectable fuel economy.

When I changed over to open drive (late 50s Corvette three speed 60 Chevy rear changed to leafs) the rear had a 3:50 rear gear, what a mistake rising the rear gear was!

It dropped the R.P.M. below the range of the cam (Isky C-4) now stepping on the throttle is like stepping on a wet sponge!

I am replacing the 3:50 third member with a rebuilt 3:70 Posi (P case) third member.

 

Just got back of the phone with the 307 owner. He says the 56 rear Axle is rebuild, the alu glide is rebuild, the engine starts right up with a Brand new starter, its got a good radiator with oil cooling. He would do a comp test before sale if i want. Sounds good. But the price now is a bit high but he is a motivated seller.

 

Will there be any difference in shifter linkage between the early powerglide and the alu one?
What about clearance of the steering colum/colum shift doing the v8 swap?

The batteri box and heater/air vents probably must go?

 

Not sure on the shift linkage since I ran a T400 in mine. But Battery box, air vents are fine to leave in. I ran some factory exhaust manifolds that cleared the steering. They dump to the rear and not down. You can also use 265 front dump manifolds. Some headers and stock manifolds will hit

 

Thanks!

 

Shifter linkage is easy to modify to make it work, probably the most easy part of the whole project.
On my 54 Chevy their aint no big problem with clearance for the steeringbox, they have mounted headers and some dents beaten on them is all to make it work.
Its a bit tight to make the exhaust go free around the steering, its aint nice done on mine so plan is to redo that.
Air / heater vents tubes are removed on mine, but it aint impossible to make that fit either, but it works fine without.
Not sure where the battery tray is located original on yours but on my 54 its on right side beside radiator

 

The cheapest way to clear the steering gear when putting a small block Chevrolet in a '49-'54 passenger car is with a LH exhaust manifold from a '55-'56 265. Chevrolet's original plan was to debut their new V8 in the '53 models, and the exhaust manifolds were designed with that in mind.

 

307 with aluminum PG, and 56 Chevy car rearend is a good choice. Little more work to get it all installed. But much better parts availability and more modern design. You will probably get same gas mileage as a 235, except you have more power and rpm capability. For highway speeds, if you can find it, can swap the rearend center section for a 3.08 or 3.36 ratio. The 56 rearend is probably 3.70 currently. Open drive is better than torque tube in my opinion.

In my 52 Chevy Ute i have a full pressure 235 adapted to a T5 and a 56 car rearend. The overdrive works well with the 3.70 and the 235. It's all interim setup until I do a V8 swap.

 

So the swap needs the following:
-Cut and grind of the firewall bracing
-Motor mounts and crossmember for gearbox(Walton maybe) Or maybe the alu glide mates up to the orginal glide mounts?
-Front dump manifolds
-Cut and move the parking brake bracket
-Drill the axle guide pin offset.
-The gas linkage probably needs redesigned.

 

Suggest you look into this organization: https://www.nationalchevyassoc.com/V8 if you plan to put in a SBC. They have exhaust manifolds specifically for this conversion plus motor mounts and a kit to install the diff that you are considering.

 

Thanks! I will look.

 

A 55-57 throttle arm and foot feed works perfectly on a 49-54 firewall for the conversion. Many restorer parts for the 55-57 offer them.
The aftermarket went to cable systems which also worked when a TVS cable was needed.

 

Cool!
Alliance discount?

 

Thanks. That helps alot.

 

Must Say, thanks to everybody. So much help and good ideas here. And so happy you guys share your knowledge! Means a lot!

 

Looked and liked a lot! And theres a lot that i need. Thanks!