350 to 396 (Coil Springs, MotorMounts?)

[Branman1971]

Plans have changed again and I managed to get my hands on a rebuilt 396 so it looks like my old 350 might be put on the shelf. I now have an 83 1/2ton crossmember and all components in my 61. Do I need to get more beefy springs for the extra weight? Will the motormounts and perches from the 350 work for the 396? Thanks all!

[kieth]

I do not know about the motor mounts (you might ask in the engine drivetrain section) but I would look up the front springs for a 454 engine for a later model front end and see what it took.....that should get the correct spring rating but says nothing about height.......others may have a better solution....or experience....with this issue....Kieth

[Branman1971]

I looked up a 1990 454 SS which is a shortbed truck with a big block. The spings shown for it are quite beefy, compared to mid 80's pickup or even Burbs. Looks like I will need to get some bigger springs. Im sure someone here has dropped a BBC in their 1/2 ton Apache.

[1963c-10]

I can get you a part #. They were ordered from Classic Parts in 2009, part # 74-473. sold as 1/2 springs for big block. I can get a moog part # off the box when I get home. I believe they were rated for around 2600lbs and load per inch was around 1000. They are for stock height w/big block. If I remember right when I was doing my research, they are pretty much a 3/4 ton -1 ton spring.

[Branman1971]

That would be great 1963c10! That's about what the 454SS springs are. .900 thick and rated 1200lbs.

[1963c-10]

No problem. I have the box sitting out at home as I've been working on getting the crossmember ready for paint. Rain and cooler temps will stall paint until maybe this weekend. And reassembly next week if all goes as planned. I'll get some pics and numbers for you when I get home.

And the 396 is a great engine....I've had a few. Miss the one I had in my 69 chevelle ss the most....even though it was an automatic car.

[Captainfab]

The springs from a 1990 likely will not fit correctly since that suspension is totally different. If you want the front to be up at aprox stock height, I would look at stock '73-'87 C20 springs with a 454. With my '66 Suburban I just left the original springs in it and the extra weight of the 454 dropped the front 1-1/2 to 2".

[1963c-10]

74-473 is the only # on the box, and I believe its a classic parts #. The springs are 13.5" total length from cut end to cut end and 3/4" thick. They are a nice part, except the factory paint. It's just flaking off, so I will strip them down and repaint this weekend.
2600# load and 1016# per square inch is what the website shows for weight.

I'm just about down with the crossmember (needs 1 more coat of paint), so I'll let you know in a week or so fun they'll be to compress to install. I'm rebuilding the croosmember and installing as 1 piece w/disk brake upgrade and all new front suspension. The big block /new trans swap isn't far off.

[MisterC]

Check out Chevy Fleetside's build:

http://67-72chevytrucks.com/vboard/s...d.php?t=259536

He has a ton of information in there and it's very well done.

[Branman1971]

Thanks guys!