ENGINE SWAP 307 TO 396

68 427 · Poncho Master!

ENGINE SWAP 307 TO 396

4SPEED427 · A Poncho Legend!

I have done this, but I hope I can remember it all.....

Just unbolt the mounts from your engine and bolt them to the 396. It will drop in.

The flywheel from the 307 (if the 396 doesn't have one) will fit. However, they are likely different diameters so you have to use the matching flywheel and starter from either the 307 or the 396. Likely the easiest is to use the 307 stuff if the 396 is incomplete.

I am not sure what oil pan you have. It needs to be correct to clear the crossmember. Hopefully someone here has a picture of one that is correct.

Transmission bolt pattern is identical.

Distributor interchanges.

All accessory brackets and pulleys are different with the exception maybe of the water pump pulley.

How complete is your 396? Do you have a picture of it?

4SPEED427 · A Poncho Legend!

Of course the exhaust is different at the front where it meets the manifolds.

All the electrical is the same although the alternator wires may be in a different spot depending on the year of the brackets on the 396 (opposite side starting in 1969)

seventy2plus2 · Canadian Poncho Superstar!

I did a big block transplant in my 70 2+2 convertible so can offer some advice (350 upgraded to 454). The engine itself was a direct bolt in, same pertches, etc. The transmission can pontentially be another story. You said presently it's a powerglide, what tranny are you going to use with the 396? Check your frame to see what it has for cross member mounts. If you go with a turbo 400 (which is typical when using a big block) you'll need to use the rear mounts if so equipped. A turbo 400 is longer, which then effected the park brake cable set up. I had to lengthen the front cable, and got a shorter intermediate cable from a turbo 400 car so that wasn't too hard. (if you are going turbo 400 and need rear frame mounts, I can probably help you out. In 68, they're the same as the front mounts)

The 396 will be significantly heavier than the 307, and will drop the front end. You may need to change your front coil springs to lift if back up again.

You may be able to get away with using the small block rad, but you may need to upgrade.

68 427 · Poncho Master!

THANX GUYS. THE ENGINE WAS IN A '64 CHEVELLE AND IS MOSTLY COMPLETE. I FORGOT ABOUT THE OIL PAN! WILL HAVE TO LOOK AND SEE IF IT MIGHT WORK. I HAVE A LARGE ASSORTMENT OF BRACKETS AND PULLEYS SO I CAN PROBALY MAKE SOMETHING WORK. THE 307 HAS HEADERS NOW AND I HAVE A SET FOR THE 396 SO EXHAUST WON'T BE TO TOUGH. I DO HAVE A TURBO 400 THAT CAME WITH THE ENGINE BUT I'M GOING TO STICK WITH THE PG FOR NOW. SORRY NO PICS.(REALLY NEED TO GET A DIGITAL CAMERA!). ANY OTHER THOUGHTS?

MIKE

seventy2plus2 · Canadian Poncho Superstar!

using the powerglide will simplify the potential trans mount, park brake cable, and driveshaft issues.

4SPEED427 · A Poncho Legend!

Any brackets on the engine? If so, I'm wondering if it was/is 68 and down short water pump or 69 and up long pump. The pulleys have to match the style of water pump.

68 427 · Poncho Master!

THERE IS NO BRACKETS ON IT. I HAVE A COUPLE BOXES THAT CAME WITH IT THAT HAVE SOME BRACKETS, PULLEYS, AND ODDS AND ENDS. WILL HAVE TO CHECK AND SEE WHAT I HAVE. THE ENGINE IS A '72 402 FROM A PICK-UP TRUCK. NOT SURE WHICH WATER PUMP IS ON IT, WILL HAVE TO CHECK IT OUT.

MIKE

gparis7 · Canadian Poncho Superstar!

I once swapped a 307 for a 454 into a 68 Impala. Agree with everything seventy2plus2 said. Powerglide or T350 will make it easy; swapping to a T400 complicates changeover due to length, yoke style & position of the trans crossmember. In the case of the T400, should you decide to go that route at some point, you'll have to weld brackets onto the frame of the 68 chassis to accommodate the trans. (Some 69 frames have mount pads for both the short & long transmissions). I used the 307 rad but the car had A/C so it was adequate. The only thing I had to fabricate at the time were the mountings for the rad, as I did not have a big block spacer with the correct offset.

-- Edited by gparis7 on Tuesday 28th of April 2009 06:20:03 PM

68 427 · Poncho Master!

THANX GUYS. I'M GOING TO DO THE SWAP @ A BUDDIES PLACE SO I JUST WANTED TO GET MY DUCKS IN A ROW SO AS NOT TO TIE HIS GARAGE UP FOR TOO LONG. ANYONE HAVE A PICTURE OF THE PROPER OIL PAN?

MIKE

Beaumont4008 · Uber Guru

68 427 wrote:

THANX GUYS. I'M GOING TO DO THE SWAP @ A BUDDIES PLACE SO I JUST WANTED TO GET MY DUCKS IN A ROW SO AS NOT TO TIE HIS GARAGE UP FOR TOO LONG. ANYONE HAVE A PICTURE OF THE PROPER OIL PAN?

MIKE

Guys correct me if I am wrong , As it was already in a chevelle it must have a A body oil pan and will fit in a B body. The problem is when you use a B body pan in a chevelle it will not clear the cross member.

65Camino · Uber Guru

Are you taking notes Ray? Or are you still going ahead putting that 400 in that we got?

68 427 · Poncho Master!

Guys correct me if I am wrong , As it was already in a chevelle it must have a A body oil pan and will fit in a B body. The problem is when you use a B body pan in a chevelle it will not clear the cross member.

STILL HAS THE CHEVELLE PAN SO I SHOULD BE SET.

MIKE

2qwik2c · Poncho Master!

Dug out my B body BB oil pan, here it is.

Beaumont4008 · Uber Guru

See that midle step on the b body pan. That is not there on the A body pan . Thats why the B body pan will not fit the A body but the A pan will fit both.

Astro Jet · Poncho Master!

65Camino wrote:

Are you taking notes Ray? Or are you still going ahead putting that 400 in that we got?

OK, what did I miss here? confuse

Where is such 400? Details?

427carl · A Poncho Legend!

400? thats a lot of cubes! is it a sbc or bbc

68 327 4spd · Poncho Master!

don't know if your interested but i have a 396 out of a 68 impala,think its a late april motor for sale,its complete but needs a rebuild, it would be the proper year for that car.

68 427 · Poncho Master!

68 327 4spd wrote:

don't know if your interested but i have a 396 out of a 68 impala,think its a late april motor for sale,its complete but needs a rebuild, it would be the proper year for that car.

NO THANX. I'M JUST TRYING TO USE UP SOME STUFF I ALREADY HAVE. I WOULD BE INTERESTED IN A 3 OR 4 CORE RADIATOR IF YOU HAVE ONE.

MIKE

427carl · A Poncho Legend!

68 327 4spd wrote:

don't know if your interested but i have a 396 out of a 68 impala,think its a late april motor for sale,its complete but needs a rebuild, it would be the proper year for that car.

How many monies?