Thread: Engine mounts - changeover from 6cyl to V8

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Ive just bought myself a 58 Biscayne with a 6 cyl 3 speed (column). I have a 350/350 to changeover. I need to find out about engine mounts for the V8. Ive been on the phone to a hot rod shop here in Australia but they don't make brackets for 58's. One guy used 64 Pontiac brackets. Someone else has said I need engine towers and brackets. My question is do I need the engine towers and brackets or just the brackets? I know with the 57 Chev you only need engine brackets but maybe because the 58 has a crossmember in the chassis, thats why I need the engine towers.?????? I also need mounts for the trans.

While Im at it - can someone point me in the direction of finding out about interiors for 58's? I have found a website that shows the different interior combinations for 57's but nothing for 58's. I know Ive picked a difficult year but I love em! The interior has been redone but I don't like it (red vinyl) and I would like to go with a combination of leather/material. I have a workshop manual but it doesn't say anything about interiors.

There were only 1600 58 Biscaynes imported into Australia and they were all 6 cylinder 3 speed manuals. They aren't that popular here. I recently went to a Super Chevy day but there was only 1 there!

Thanks anyone and everyone - Trish

Trish, as I recall for working on these cars years ago, the frame mount section (towers) are the same and all you need is the motor mounts (brackets), and......it seems to me that they are the same for quite a few years from 58 on up. I could be wrong cause it's been a long time since I wrenched on any old Chevy's. JMO.

Thanks, thats what I thought. I wondered whether the guy who used the 64 brackets would have also used the towers. I guess Im finding it hard to figure out why you cant just bolt the motor mounts straight to the chassis like other models?!. Trish

Come on all you Chevy Nuts. Help this gal out. I'm really not sure if I gave her the right answer or not. You guys ought to know. Jump in here and help Trish.

P.S. Trish, I sent a PM to a friend of mine that may be able to give a definite answer. Hang in there, Sheila.

Ah, Denny, your a life saver. That's what I thought. the V-8 and six used the same mounts. Thanks bud. Now, we just got to wait for Trish to see this. It's early morning there.

Oh Oh, maybe we should try to find her some frame mounts to mail to her.

Denny, I just assumed from the www.suspension.com addee, that since the motor mounts for a 6 and a V8 were the same that the frame mount were too. Oh, well, learn something new everday. Hehehe. P.S. good night. I's a tired puppy.

I did a couple of 58 swaps here's what I remember.

The 6 cyl frame mounts are taller than the V8 ones. Although the V8 can be mounted to the 6 cyl frame mounts it sets the engine up too high (it can be run that way, but screws up the drive shaft angles). V8 frame brackets can come from any full size chevy from 58 throught at least 66 and should really be used. Motor mounts are the same and are the early style, (NOT LIKE THE ONE IN THE PICTURE ABOVE).

I used 70 Impalla 350/350 tranny mount, at most you may need to elongate the slots on the rear crossmember a little.

Your drive shaft should be OK as long as the TH 350 has the short tail shaft, otherwise you will have to shorten the front haft of the shaft.

As far as interior info, check E Bay and look for sales info. A lot of that shows different interior options available.

Just a little general information for you.

Your 6 Cyl springs should do fine. If your rebuilding the suspension and want the car to really handle, add a set of 348 springs (you'll need to cut a little bit off the front coils to get the frond end ride height right) and add 1" frond and rear sway bars.

A disc brake upgrade for the front is really the way to go on these cars. If you wish to retain the drums and have problems finding the Ball Bearings for them (a rearl pain and expensive here in the states) Dig up a set of 63/64 front hubs, there a bolt on and convert the car to tapper bearings. Grabbing the backing plates and drums at the same time will also give you bigger front drum brakes.

I don't know about the export cars, but the domestic 6 Cyl models came standard with vacume wipers instead of electric. If you do a change over you will need not only the electric motor and switch but also the linkage arms.

Thank you so much guys I really appreciate it! Im just having a coffee and absorbing everything you've all written.

I thought you might be interested to know:

I bought a disc brake conversion kit so I can convert the front to disc brakes (early model Holden/GM). I dont know how you guys go with conversions over there but here once you changeover from 6cyl to V8 you have to change to disc front end (by law). The car has to go to Regency which is our Government Transport Department. You have to submit an "application to modify" form detailing everything you are changing i.e motor, trans, front end etc. They approve it "in principal" and then the car has to be booked in for inspection. With luck the car gets passed and if not it is defected and has to be rectified. I am not doing anything to the motor at first, I am leaving it Chevy orange with the standard carby (Rochester 2 barrel) to get it passed at Regency but once I bring it home again - yippee! I have been given an Edlebrock performer manifold and Holley 650 carbie. I would eventually like to pull the motor down and fully rebuild it (warm, not stinkin) but my husband keeps saying "you don't want a real hot motor do you?! Actually I would!!!

I want the car to look as standard as possible when it goes to Regency because those guys are notorious for being picky and difficult! You can't even have a bonnet scoop here in South Australia (in the other states it is different). You can only go 20% bigger in engine size than what the car came out with, without having to get an Engineer's certificate. Engineers have to do things like chassis stress test, brake test and lane change all at approx AU $2500. I guess the good thing about an engineers certificate is that the car will be passed.

Anyway that was a bit of trivia for ya. Thanks again and I'll be in touch once Ive done the changeover to let you know how I went.

Trish