jaredi

Hi guys, I have an 86 IROC I'm planning to convert to carb. I had been optimistic about EFI and had originally planned to do a HSR but I've been thinking I want something that I can tinker with a little bit. Anyway, the car is getting a 350 and 700r4. The units in the car now are probably garbage so I'm going to eliminate them as a source of concern.

My question is, what engine should I pick up, and what transmission. The things I'm considering are an older longblock built by someone else, a Vortec longblock, a Longbock from a Camaro/Firebird, or an LO5 (least preferred choice). I know that older engines used a two piece rear main and that there are some differences in the transmission to accommodate. I have always assumed that you can't use a 1piece seal trans with a two piece motor or vice-versa. Is this part correct? I have been looking at late model 700r4s to make sure they got all the part upgrades and ensure that it will hold up for a while, but these are typically all 1-piece seal units right?

So basically what I'm asking is, if you guys were picking a engine/trans combo for a carbed setup, what would you look for? I'm trying to keep cost down as much as possible so money is a key factor.

I'm leaning towards the Vortec route at the moment but there seems to be a pretty good deal on some older engines in the classifieds and locally but are the late model 700r4s going to work with them or will I be stuck with an early 700r and if so are the early ones any good?

Thanks for your input!
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I should really change my sig... Done

jstoltz

iTrader: (16)

there is no difference. you can use a 283 from a 1955 sedan with a 700r4 from 1992 or a 4l80e from a 2007 1 ton for that matter. just get a decent deal on a motor and use a 700r4 since you already have one in it.

five7kid

iTrader: (14)

Well, that's not entirely true. First, the 283 didn't come out until 1957, and second, they weren't properly drilled for the starter. But, other than that, you are correct - the rear main seal type doesn't affect whether a TH700 will work with a 350. You just need the proper type flexplate.

The '80-up blocks seem to be of higher quality than the earlier ones. So, that's one reason to go that route. After that, it's a matter of intended use and budget that dictates where you go. You could do any of the shortblocks with upgraded Vortec heads from sdpc2000.com, any of a number of aftermarket heads, 3rd gen heads, etc. Most any truck head, swirl port (LO5), and any 70's heads should be avoided.

bluegrassz

iTrader: (3)

I have a friend that just build a .060 over 350 with vortec heads. It is ready for a carb and accesories. He is located in London just off I-75 if you are interested.

It has new hyper pistons, its a 010 4-bolt block, vortec 906 heads that have been P&P clearanced for larger lift cams. The cam/lifters are new 292h cam. It has new roller tip rocker arms, double row timing chain, oil pump. It has a vortec rpm airgap style intake. The rings and bearings are all new.

PM me if you are interested.

jaredi

Thanks for the info guys, that bit about the transmissions being able to be used is a relief. I'll keep everyone posted as to what I end up doing.