I have an 86 IROC that is going to get a new engine. I know the 350 will fit just fine, but what about the 400sb? Is this a bolt on project or are there engine compartment structural changes required?

Any other caveats? I read the other 400 discussion going that addressed overheating issues, so I trapped all that info. What about the transmission, are the bell housings the same on the 305 and 400?

I'm also considering dumping the TPI in favor of a carb so I don't have to worry about getting the to work right or putzing around with different injectors and fuel pressure regulators/pumps et al. Any good reasons to keep the tpi assuming a well put together carbuerated setup?

If ANYONE has done one of these projects I'd really appreaciate hearing about your experiences or advice. This car is going to be a daily driver, so it won't be built as a racing engine. But I do want better than stock performance from it. i.e. Cam, Headers, Intake, 4bbl, 1.94/1.68 heads, 2500 stall converter, gears etc.. Mostly bolt on stuff.

John

[This message has been edited by nt (edited 10-25-99).]

Add on: I'm looking at the Edelbrock performer package for the 400. 3701 Manifold, 750cfm square bore carb, Performer Plus cam. Is this too much for a daily driver? Also, what are the advantages/disadvantages of going with timing gears over timing chain?

Thanks,

John

John,
Depending on your budget, you may want to consider building a 331. This is your 305 motor with a 400 crank. We have done a couple and they are really very torquey strong running motors. The last one we did was in an 85 Trans Am and we used all the TPI stuff and computer. The thing runs real strong, spins tires in 1st 2nd and 3rd gear in the 700R4, yet still gets very good gas mileage when driven "normally"....just a thought. All the parts are easily available, probably would be about the same price as building a nice 400 from scratch.
Hope this helps,

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

You may want to strongly consider keeping the tpi. (Many would kill to have one...kidding). The guys over at fuelinjection.com appear to specialize in tpi. And, on their site, it says that tpi over a carb is worth 30% more power, not to mention nice idle, better efficiency etc. Yes, you may have to resize your injectors, but it may not be as bad as it sounds. Id drop those guys a line and they could tell you what size to go with.

For the street, keep the tpi. It will only rev to 4500-5000 rpm stock, but if you stay with a very mild cam, you'll have plenty of low end power.
Bill's idea with the 331 sounds interesting...I think this would work better with the TPI, and you'd get better mileage too. Not to mention not worring about overheating. Stay with a cam around 268-276 duration, and you should be able to use the stock torque converter, too! (hi-stall lock-up converters=big bucks!!)

That 400 overheating issue sounds like it's not a problem if I use 400 heads and a 3 core radiator. But since I've never ran a 400 I'm not positive about that. My real concern with the TPI is getting the computer/pump and injectors working correctly. Curious to know why you suggest TPI for a street car? I know there are some very very quick and useable carb powered engines. Seems that only benefit to TPI is efficiency and computer adjustment.

Thx

To toss a TPI in favor of a carb is a step in the wrong direction. Why take something that works so efficently, and toss it for the sake of an old system? There are plenty of people putting TPI units in old 57 Chevy's, etc, and street rods. These people are taking advantage of a modern system that works. My suggestion would be to pick up a Hot Rod, Car Craft, Chevy High Performance magazine, etc. and read, read, read. You'll change your mind about the TPI. A good TPI unit with injectors, fuel rail and wiring has been going for about $800-1000 around here in Minnesota, and they are hard to find.

Fuel injection is here to stay, and will soon be the norm. Carbs will eventually be looked upon as relics in the hot rod world. Check out a few things before you ditch it, and you'll find that it's not that hard to do if you do your homework before you start. If, after you've researched everything, you still want to do the carb thing, I've got a Holley carb/intake setup that I'll swap you even-up for the TPI.

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70 & 1/2 RS
SB406 & M20 4spd
9" rear

70 Malibu 350/TH400

Gold member #103




[This message has been edited by Scooter (edited 11-02-99).]

Scooter: Thanks for the comments, all advice is--without question--appreciated.

Do you know if the TPI manifold from a 305 will bolt up to a 400 block? If not, what do I do to deal with that? Do you know how I can get the computer to work correctly for the new engine? And where do I find out how to get the injectors and fuel pressure right?


Thanks again,

John

The TPI manifold will bolt up to the correct heads. The block is not the issue. If you get the correct combo of heads, block, etc. anything will bolt up. As far as the injectors go, you'll most definately need 350 injectors. The later model heads that accept TPI have a different angle on the center bolt holes (intake to head) than the earlier heads do. There are a number of companies that offer aftermarket heads that accept the center bolt valve covers, as your TPI will need. All that is required to bolt these heads to a 400 block is to drill steam holes in the heads. You can use a 400 head gasket as a template to drill these holes. There are so many possibilities for small blocks, it is unreal. Good luck in your challenge, it can, and has been done before, so like I posted earlier, check out the magazines, they have plenty of info on these swaps.

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70 & 1/2 RS
SB406 & M20 4spd
9" rear

70 Malibu 350/TH400

Gold member #103




[This message has been edited by Scooter (edited 11-05-99).]

are you selling your TPI if so how much will it fit a 89 305

Keep the TPI

The 400, in my opinion is the way to go. I have an 89 Iroc that I just finished putting a 331 in (327+.030") I'm running a turbo 350 trans. everything block wise is the same as your 400, so everything should bolt up. I swapped the TPI for a Holley 4bbl. The TPI was going to run me well over $1500 to do it right, and the carb and intake were around $350. If you have the money, do the TPI, but if you dont run a carb. PS...You'll need to scrap your Computer controlled Distributer, if you want it to run right on carburation. The main reason for my swap was that I wanted to be able to rev high....and it does (redline is set around 8000 rpm), but peak HP is around 7000.

Dave is correct on the TPI, they provide much more bottom end torque than carbs. Why?, just the name tells all, "Tuned Port Injection", with the emphasis on tuned. The runners are a specific length that emphasizes bottom end torque.

If you increase the CID of the engine, but want to keep the bottom end torque, then increase injector size, open up intake & exhaust and replace the stock chip.

If you want to move your torque range up to a higher rpm, then you replace the runners with a shorter length, aka a "mini-ram".

As previous posts suggest, fuel injection is steadily replacing carbs. You're metering in a specific amount of fuel PER cylinder with TPI, which you can't do with a carb.

Just my .02 worth


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67 Camaro LS6 454/TH400/12bolt 3.73
1989 TransAm 5.7L WS6 W/all the options