350 swap to 455 what needs to change?

[shaks 442 clone]

i found a core 455 needs a complete rebuild and i was wondering my car has a 350 in it right now and i put eibach lowering springs on it my first question is will the 455 squash those springs?

also what else would need to be changed over

thanks for the help in advance

~shak

[joe_padavano]

Originally Posted by shaks 442 clone

i found a core 455 needs a complete rebuild and i was wondering my car has a 350 in it right now and i put eibach lowering springs on it my first question is will the 455 squash those springs?

also what else would need to be changed over

thanks for the help in advance

~shak

Since this was a factory option, it's a bolt-in. The thing that throws most people is the motor mounts. You can either use the existing 350 rubber motor mounts with the existing metal frame mounts or you can change everything to the correct 455 motor mounts with matching frame mounts. Just DO NOT mix 455 motor mounts with 350 frame mounts - that's where the problem occurs. The only real difference between the 350 mount setup and the 455 mount setup is the 455 parts are beefier (which is why the different frame mounts are needed) but either style, used as a matched set, will position the motor correctly.

All the accessory brackets of that vintage are designed to fit both big and small blocks, usually through the use of two different sets of holes where necessary. You'll need big block exhaust manifolds or headers and you'll want a high torque starter, but everything else is the same.

[shaks 442 clone]

so the 455 will drop right into the 350 mounts?

[joe_padavano]

Originally Posted by shaks 442 clone

so the 455 will drop right into the 350 mounts?

Originally Posted by joe_padavano

You can ... use the existing 350 rubber motor mounts with the existing metal frame mounts...

I think that's a yes...

[texasred]

Auto Transmision...beef up a TH-350 and it bolts right up or get a TH-400 and shorter driveshaft.

Manual transmission....it's all good to go.

C.J.

[shaks 442 clone]

i have a th 350 already and thanks joe u know me i just need a straight forward answer or else i will get lost lol

[Omicron]

Wow, sounds amazingly easy!

So how about a GMPP big block crate motor, say a 502ci. Same story?

[texasred]

Now your're talking a Ch#vy motor. BIG difference. Do a search on other posts about this...it's a long and (for some) sore subject.

C.J.

[joe_padavano]

Originally Posted by Omicron

Wow, sounds amazingly easy!

So how about a GMPP big block crate motor, say a 502ci. Same story?

Nope.

Olds motors all have the same basic external geometry and hard points. Chevy motors are completely different. Yes, the Cutlass frame is the same as a Chevelle, but you'll need all the Chevy brackets, accessory mounting hardware, trans, exhaust, etc, etc.

You'll also need a different forum, since few here are in favor of Chebby swaps.

[442Harv]

Just did this change on my Vista. It was no problem, but I used non notched vanle covers, and it is tight by the AC cover, and I bumped it, and put a small crack in it, so be carefull. I had to also put a spacer on the powerstearing bracket. Also I put a 4 core radiator in.

[hurricane]

Originally Posted by shaks 442 clone

i found a core 455 needs a complete rebuild and i was wondering my car has a 350 in it right now and i put eibach lowering springs on it my first question is will the 455 squash those springs?

also what else would need to be changed over

thanks for the help in advance

~shak

i well take pic of my 57 7-17-07
i have a 55 cu olds in my car and r-400 trans work real good i had to drop my car 2'' the 455 is lighter thin the 371 you can see it on the forum pic of my 57
super eigthy eight

[texasred]

A 455 weighs 107 lbs more than a 350.

And good to "see" you over here Harv. You may remember me from 442.com and OCA Seattle....or not...

C.J.

[Omicron]

Originally Posted by joe_padavano

Nope.

Olds motors all have the same basic external geometry and hard points. Chevy motors are completely different. Yes, the Cutlass frame is the same as a Chevelle, but you'll need all the Chevy brackets, accessory mounting hardware, trans, exhaust, etc, etc.

You'll also need a different forum, since few here are in favor of Chebby swaps.

Not saying I'd DO one, just wondering if it were as easy as dropping in a 455, since 455's aren't still made but 502's are becoming cheap and plentiful and come with warranties. I've always been a 455 fan anyway, this just came up from yakkin with a friend who thought the 454/455/502 blocks were the same. Sorry for the hijack, thought it would be a short answer.

[joe_padavano]

Originally Posted by Omicron

...this just came up from yakkin with a friend who thought the 454/455/502 blocks were the same.

Let's all remember that in the 1960s and 70s, each GM division had their own unique engine designs. The Buick 455, Chevy 454, Olds 455, and Pontiac 455 are all completely different designs with different bore/stroke, different castings, and nothing interchangeable (except the Delco distributor cap). A casual observation shows that the Buick has a front-mounted distributor, the Pontiac has a separate valley pan with raised intake, and the Chevy has a different bellhousing bolt pattern. All four makes have different motor mounts as well. Since the A-body cars were sold by each of the four makes, the frame has pre-drilled holes for these mounts, but the actual brackets are different.

Same thing for the 350s from each division.

[Omicron]

Originally Posted by joe_padavano

Let's all remember that in the 1960s and 70s, each GM division had their own unique engine designs. The Buick 455, Chevy 454, Olds 455, and Pontiac 455 are all completely different designs with different bore/stroke, different castings, and nothing interchangeable (except the Delco distributor cap). A casual observation shows that the Buick has a front-mounted distributor, the Pontiac has a separate valley pan with raised intake, and the Chevy has a different bellhousing bolt pattern. All four makes have different motor mounts as well. Since the A-body cars were sold by each of the four makes, the frame has pre-drilled holes for these mounts, but the actual brackets are different.

Same thing for the 350s from each division.

A'yup, I recall said history. Question was more pertaining to a modern motor, the *GM* 502, but I got it answered anyway thanks to you and others here.

Originally Posted by joe_padavano

... Since the A-body cars were sold by each of the four makes, the frame has pre-drilled holes for these mounts...

Interesting, didn't know this tidbit. Makes sense though!

[joe_padavano]

Originally Posted by Omicron

A'yup, I recall said history. Question was more pertaining to a modern motor, the *GM* 502, but I got it answered anyway thanks to you and others here.

A big block Chevy is a big block Chevy is a big block Chevy....

[shaks 442 clone]

Originally Posted by 442Harv

Just did this change on my Vista. It was no problem, but I used non notched vanle covers, and it is tight by the AC cover, and I bumped it, and put a small crack in it, so be carefull. I had to also put a spacer on the powerstearing bracket. Also I put a 4 core radiator in.

i replaced my cutlass's 2 row with a 4 row also lol

[joe_padavano]

Originally Posted by 442Harv

Just did this change on my Vista. It was no problem, but I used non notched vanle covers, and it is tight by the AC cover, and I bumped it, and put a small crack in it, so be carefull. I had to also put a spacer on the powerstearing bracket. Also I put a 4 core radiator in.

I've used non-notched valve covers with no problems, but those were all non-A/C cars. I've never had a problem around the power brake booster, either. The four row is a must, or else a good aluminum radiator.

[442Harv]

Texasred, yes I remember you . The Vista I had there is the one I put the 455 in. Also back to the other post, I used non notched valve covers both sides, no problem , for fit, other than I said before, I did hit the AC box and put a crack, but That could off been pervented, if we were more carefull, also probably should of put the heater control valve in after, would off helped a little also.

[mcutlass1969]

First I would say. Listen to these guys on this web page. They walked me through this conversion.

One other note. I had to move my breaks porportioning valve to make room for the headers on the drivers side.

[shaks 442 clone]

ive actually spoken to a couple of people around town and they talked me out of swapping the 455 in

they said it was just be more trouble then pleasure for a person of my age on my budget and i agreeded with them

it makes sense with a nice cam an edelbrock carb and intake i should be happy heck all i really want out of the car is just for it to be a nice sport around town that can brun some rubber haha

so im just gonna stick with the 350 until im finacially set to do the swap right and not have to rig anything