First of all, would this swap make sense? I have L98 91 GTA, I also live in an emmission controlled state. I guess a few of my questions would be:

Would a stock rebuilt 1980 400 chevy really be an advantage HP and/or torque wise?

Would an 1980 400 have all of the proper things for me to retain all of my existing smog crap?

If yes to the above 2 questions, would vortec heads be a bolt on with this (in place of the 1980 stock heads)? and still theoretically be emmisions friendly.

If yes again, would the stock cam be enough?

I am not really looking at a certain HP that I want, I just want to get enough motor in the car to be able to keep up with rustangs and newer f-body's. I have considered a new stock 350 bottom end w/cam and heads. I have looked at that SPDC 360 tpi vortec motor.

I have 78,000 miles on the original engine, really no mods other than the Banks cat back exhaust. I know some motor work is in the future since she smokes a little when I first fire it up after sitting for 3-4 hours. Sorry for the lenghty post. Any input and/or links to some good places to look for motors would be appreciated. (I have read some posts on the 400 swaps that some of you have done and it got me drooling!)

 

If you are planning on leaving the stock TPI on, IMO there's really no point to go with a 400. TPI, especially in stock form can't support the type of air flow needed for the 400. There are several people on the boards that have TPI 383's, but have ported intake, siamised runners, bigger TB.

Yes you could use vortec heads on the 400, you would have to get the SPDC lower vortec intake to be able to bolt the TPI up. To really make good power I'd think you'd need a SR or MiniRam

With a stock cam and TPI I think you'd probably power peak at 4000-4500.

I don't know anything about the SPDC 360TPI engine.

400's need alot of air to make good power. I love my 406, but I also have a carb.

 

I love the thought of a 400, but the more I look at that SPDC 360 tpi crate motor the more I like it. For $3500 shipped to my door and no emmissions worry's. It seems like a decent power maker too. It's claimed to be made for stock tpi/tbi cars, and claimed to have 360 hp, and 416 lb/ft. of torque. Vortec heads & LT4 hot cam. What do ya think? Check it out

http://www.sdpc2000.com/cart.asp?act...art&catid=1577

 

The few hours it would take to replace the valve stem seals isn't sufficient justification to replace the engine.

Also note the SDPC Vortec TPI is not emissions certified - not exactly "no emmissions worrys". And they got that power with long-tube headers (which also are not emissions-legal). And PROM tuning is required.

From the linked website:
"Requires the use of EGR kit SD3816, headers and 350 injectors. Dyno tested with Edelbrock runners, 52mm throttle body and 1 7/8” headers."

From their Vortec TPI base link:
"This intake is NOT legal in California on any pollution-controlled motor vehicles, nor has it been approved for any pollution-controlled applications in any state in the USA."

A wee-bit more than $3500 when you add it all up. And not emissions-legal, technically.

 

I didn't notice that little disclaimer under the egr kit info. I do agree that tossing out the 350 thats in there at 77k is a bit premature, but i'm looking at within a year doing something. This all started with the thought of buying a supercharger a few months ago. First let me say that this isn't my daily driver. I have put about 4k miles on it in 2 1/2 - 3 years time. I thought a supercharger on a 77k motor was asking for trouble. So then I thought I definately need a rebuild before a supercharger, but holy cow, a rebuild kit with forged pistons/crank was looking to be 1200-1500 bucks + labor + 3000 for a charger. So then I decided for that kinda money, I would rather go with just all motor and forget the charger. But with this emmissions garbage it really limits the options. I could always just take the chances of passing testing, and if I fail, just show a "receipt" that I spent $500 to try and correct it. If it still fails after spending $500 , you just get a waiver. But I think it would pass with the linked motor I posted earlier(with some minor tuning). With all this said, do you think thats a decent bang for your buck motor?

 

Depends upon the rigor of the emissions inspection in your area. If they aren't particular about what's under the hood as long as it passes sniffer, that engine would pass easily if tuned properly.

With regard to bang-for-buck, that's a personal decision, but IMHO that's the best way to go about Vortec TPI if you're set on that direction.

Oh, you don't "need" forged pistons with a supercharger, necessarily. Keep the boost low, mixture rich (at least, never lean), and you'll make more power with a stock engine w/charger than you would with that SDPC Vortec TPI package. Remember, that HP rating is flywheel gross, rather than real-world net like the factory ratings.

 

Dude you are nuts to replace your block if it only has 78k miles. Buy yourself the Vortec heads and slap them on your shortblock. With the miles you have, and the fact that it's not your daily driver, your best "bang for the buck" as you call it would be to get new heads and a cam. Your stock short block has a ton of life left in it.

 

It's been a few months, but I did the math on TPI/Hot Cam/Vortec base-ready Vortecs. including 1.6 rockers, gaskets & such. You're getting a very good deal on the short-block in that package.

You could get the same power for the money by upgrading the L98 with the TPI goodies, head porting, and cam.

But, Vortec lovers don't like to hear that.