friend of mine is sellin me a sbc 400 short block bored .060 over. of course w/a 3.73 posi rear and a 750cfm carb you can kiss driving on the streets goodbye. the motors was pulled out of a 10.5w outlaw to be replace w/ a big block so its in pretty good shape. i'm planning on keeping my vortec top end and my 680cfm carb. of course the cam in the block now is HUGE!! so i need suggestions on what size i should go w/ to maintain some street ability. and a good compression ratio as well as a gear set that should be pretty good street and track wise.

oh yea the th350 is being exchanged for a 700R4 if that helps any w/ the gear selection


all suggestions are welcome.

-J$Money

 

Build the shiz out of that 700R4 'cause they can't handle a hot motor in an F-body, let alone a truck. I know I hated my 700R4 on more than one occation when I owned my '86TA. Stupid trans to begin with and even more stpuid that the same basic trans design is in my '03 Silverado SS. Not sure what GM was thinking there...

For the engine, keeping a Vortec top end is going to kill HP (unless they're the Bowtie GM Performance Vortec castings in 220cc large port that OBLITERATE any stock Vortec casting). Are your heads modified for higher lift?

If you're dead set on keeping the vortec smaller ports, you're going to want something smaller than 550 lift and 230 duration because even ported the stock vortecs stall out past those numbers. This would mean you're building a low RPM torque monster and you want to go with a high quality stall not much more than 2500-2800 at most.

The 3.73 actually wouldn't be to bad with the 700R4, except that the 1st gear is rather low ratio and with the 400 built for low RPM TQ with the vortec heads, you'd smoke the tires like crazy... if it hooked up, bye bye tranny!

Truth be told, I'd sell the Vortecs on Ebay and get some of the newer Bowtie Vortecs and go to town with a bigger cam to raise the tq peak. Keep the stall under 3000 and build the crap out of the tranny and keep those 3.73's.

EDIT: By the way, in your sig... a 400 bored .060 over isn't a stroker. To call it a stroker, you have to increase the stroke from stock and go with a longer throw crank.

 

thanx for catchin that typo in the sig. it was originally 383 stroker and i forgot ta delete stroker. preciate that! yea i was planning on getting my heads ported and what not, valve job, the whole 9........ if i could get a decent amount for my vortecs i would sell'm on spot depending on how much more i had to add to get the other ones. the tranny will be built to the ****** hit, w/ every performance part possible. but now the main question is, is low rpm torque monster good for the street because that's basically all i'm using it for......

 

Spending money to modify your stock type Vortecs is going to cost you more money than buying the GM Bowtie ones brand new. They have to be cut in the spring pockets for larger diameter springs, cut down the guide for higher lift, along with the regular resurface and valve cutting work, all to have a vastly inferior flowing head.

The bare head is available as pn 25534371 for $328.95 each. They're setup for 2.00/1.55 valve sizes, which are the stock LS1 sizes if you wanted to go the used route. Get yourself good springs/retainers and you're in business.

There are some good articles on the net for "bowtie vortecs". Read what others have done with them over the past 2 years they've been out...