[85montehotrod]

How much will a stock 400 with edelbrock performer intake competition carter 650 cfm with headers how much horse power and toque will it produce?

[firestone]

What did the motor come out of?

Adam

[85montehotrod]

the motor came out of a suburban its a 400 4 bolt main the casting # is 3951511 puts out 265Horse stock. Just wondering what it would be with aftermarket intake carb and headers.

[454C10]

Headers are worth about 15 to 20hp on a stock engine. But that could be a gain only in the mid range and not on the peak power. Mid range torque is where those headers will really make a difference (maybe 40 ftlbs more). Headers will make more of a difference with a bigger cam, better heads, and intake.

Again on a stock engine, an intake and carb will gain maybe 10 hp on the top end but will give up torque under 3500rpm. If this engine is in a 4000 pound car with a 3.08 gear then stay with the Q-jet and stock intake.

The stock cam really stinks on those engines. Even a very mild RV type cam would make another 30hp over the stocker.

A little bowl work on the stock heads can be good for another 20hp.

If you pull the heads and do some minor bowl work and get a valve job, install a performer cam, performer intake, and set of headers, then you could get 350hp/400ftlb out of that 400.

[Blazin72]

What year Suburban do you have? I have a Blazer/Jimmy manual here that lists the 400s from 1975 to 1980. Since the K5s, pickups and Suburbans shared many of the same drivetrain parts I'll assume the Suburban 400 isnt much (if at all) different than the ones that were dropped in the K5s. The highest power rating I see here for a truck 400 is 175 hp meaning with the intake, carb and headers you're probably somewhere in the neighborhood of 200-210 hp. Stock torque rating was 290, you may be up to ~320 or so.

Now the question is, is this the original engine from the Suburban or did it come from something else originally? The engine code is stamped into a small pad next to the passenger side cylinder deck surface just above the water pump outlet (inlet to the block). If you can find that number we can better determine what you're starting out with. This number is different than the casting number and should look something like this: F0130UZB. That's just an example but it should be in that format.

[85montehotrod]

the stamp is a little hard to read but here you are- t0908csk or t09c8csk

[Blazin72]

If you follow the info on the following page it'll tell you the engine was built in Tonawanda, NY on Sept 08 for 1973 B-body cars (like a Caprice or Impala) Originally rated at 175hp and factory equipped with a 2 bbl.

http://www.nastyz28.com/spmenu.html

[85montehotrod]

on tracy chevy engines with the casting numbers on the back of the motor came back as a 400 4 bolt main 255-265 hp? So who's right? Cause i was told the same from my local machine shop as above.?

[Blazin72]

Casting numbers were used over a range of years. Mortec.com lists the "511" block as being used from 1970-1973. The engine code refers to engines built at certain places, at certain times, for certain vehicles. I too have a "511" block and it's engine code is T0929CAT which says it was built at Tonawanda on Sept 29, 1972, with a 2 bbl and also for B body cars. It does not list a horsepower number. However, a 1970 400 could also have the same "511" casting number but have a CGR suffix in the engine code which would tell you it was built in 1970 for C/K series pickups and it would have a rating of 265hp. In some cases the casting number may not even tell you what engine you have either. For example a block with a 3932386 casting number could have been used as a 302, 327 or even a 350 in 1969. See what I'm getting at? In your case the 3951511 casting number is 400 only, but that casting was used for trucks and cars of various power ratings over ~four different years.

[85montehotrod]

So you r saying the motor is only 175 hp motor then? I don't understand why two different people say one thing and someone else says something different, but the numbers are there so. So that means i'm gonna have to start at ground zero to find another motor to build. I'm just confused

[Blazin72]

Did the other person look at the suffix codes or just at the casting number? There still isn't anything wrong with the engine you have. Everything that 454C10 still applies. Regardless if it were 265hp or 175hp if should probably still be tore down and rebuilt. At the very least new rings and bearings, probably overboring the block as well as other machine work. Put together a a fresh new engine with your choice of cam (chosen keeping in mind your chosen compression ratio, airflow quality of the heads, intake, exhaust etc) and other parts you can still get a very good performer with little work. 300+hp with a 400 is a walk in the park... If your block is in good shape then use it.

[85montehotrod]

whats the largest cam i could put in the motor? Preference intake,exhaust lift,with stock bottom half and heads or should i go with a vortec upper half?

[Blazin72]

That depends on the compression ratio of the engine. Vortec heads would work very well but you need to drill steam holes in the head to match the block and head gasket. The Vortec heads may have a different combustion chamber size than the original heads on the engine and that would either raise of lower the compression ratio. Do you have the original heads? If you can get the casting number from them you'll be able to get an idea of how much your compression ratio will change (if at all) by changing the heads.

[85montehotrod]

Where is the # on the heads?

[85montehotrod]

Alright then somebody please give me a good engine combo that will run on pumped gas and without machining the bottom half , i'll put 202 valves in the heads or buy a set of dart heads that are already done, where do i go from here? Cam size, timing gears or roller chain?