Keith5

I have a 1988 Long bed Full Size, stock 350, e-fans, edelbrock headers, I have gotten the truck down to about 4200 pounds. I need/want to replace my intake manifold because of a broken heater fitting. I thought about going carb, but have decided to stay TBI. I have had the edelbrock 3704 before on my firebird and I don't want to go that route again.

I'm not keeping the EGR valve, what would be a good choice for me? I plan on putting a better cam in some point down the road, I don't drive my truck much(3,000 miles in 5 years). So I don't need to be overly conservitive, but I want the thing to run and run efficiently.

thanks,

Ghettobird52

only way to make a intake work properly is with a cam also. but for future reference get the edel brock rpm performer tbi. i have it on my mild built 350 (450 lift cam) and it works perfect.

Keith5

There isn't an edelbrock rpm performer tbi, the 3704 which I already had on my old firebird is the edelbrock performer tbi. Do you have a carb version of the rpm performer with and adapter plate for tbi?

I will probably end up porting my stock heads and getting something like an LT1 cam or maybe a little more aggressive when I rebuild the whole engine at a later date.

UnderCover89TBI

iTrader: (25)

stock manifold would be the best choice. If you dont wanna go the 3704, most poeple run the performer rpm carb intake with an adapter for tbi.

Keith5

Would the air gap be too much intake for the stock engine to run ok?http://www.summitracing.com/parts/EDL-2604/

gmstrong

Tuning should be fun with that intake,when i had my tbi350 i was thinking about weaiand street warrior carb intake.if you do want to get a aftermarket intake get a carb intake or the holley projection intake mani.i did the 3704 on my truck i lost some bottem end but gained so top end def isnt worth the money though.

Ghettobird52

And I'm sorry I ment the 3704. And if not that then yeah I'm
Not sure, works perfect for my setup. Hm lost Bottom end? When I swapped it with my cam I gained power in that area

Ghettobird52

And I've heard air gap intakes are not good for tbi but I may be mistaken if some one can correct me

gmstrong

well yea with the cam and intake im sure you gained hp trying adding the intake i bet you wont feel a difference i did the 3704 intake before the cam swap and didnt feel a difference so i ported the old intake and heads and stuck in a mtc-1 then sold it.so glad i did those tbi350s are weak unless you stick in a good size cam.

Keith5

I eventually want a 383, ported stock L05 heads, an LT1 cam. I guess it's between an Edelbrock performer, or Edelbrock RPM, or the Holley projection.

UnderCover89TBI

iTrader: (25)

you want to add cubic inches but only port the stock heads? you deffinately wanna upgrade the heads if you go 383, something like the AFR 195's. you can move more air with more cubic inches, so you'll need to move more air with the heads.

air gaps on tbi engines are known to be a total pain the **** to tune, and fuel puddles up in the intake if I am not mistaken.

Keith5

I want the torque, the stock heads ported with a 383 would be ok. If money allowed I'd get new heads too.

UnderCover89TBI

iTrader: (25)

You'd still have plenty of torque and more high RPM breathability too. but I understand about the money. and we are all limited by the amount of money we have.

Ron_90

Found this affordable LT1 cam if you're looking to buy one now

http://www.ebay.com/itm/Chevy-Small-...#ht_500wt_1287

I'll also add that I haven't heard great things about the air gap for TBI's either

thomas1976

In this case I would rather spend the money for the cam and heads, then for the intake manifold.

Keith5

So is the stock intake that "decent", to use with an better cam and heads? Back when I had my firebird and read these boards the concensus was that the intake was terrible.

I have an LT1 cam sitting on a shelf, waiting, but my engine didn't have the roller cam hardware stock so I'll have to do a slight conversion to use my LT1 cam.

Keith5

Can the stock intake support 275 horsepower? Is there any work that can be done to it to help it along?

thomas1976

Roller cam is easy +25-30hp over a flat tapped cam.

On top of a 275hp engine the stock TBI manifold should be just fine, now if you can find a used 3704 or performer rpm for the same price, could use it. Gains if any, will probably be less then 10hp.

Some folks here swap intake manifold and put a flat tapped cam in there roller block, go figure.

Schurkey

I have heard--but not verified--that the OEM small-block TBI intake manifold is TERRIBLE for fuel distribution. Some cylinders run rich, some run lean. Power is limited by the lean cylinders, they're the ones that knock first and retard the timing.

Any confirmation here?



I, too, have an '88 full-size long-box truck with Edelbrock headers...my plan was aftermarket Vortec heads that have the old 6-bolt per side intake manifold pattern, and the GMPP dual-plane intake manifold (have to plumb exhaust to it since there's no exhaust crossover in the heads. Can tap off the AIR fitting in the header easily enough. Thus the EGR can still be used.

Then install a GM TBI-to-Quadrajet adapter from a TBI 454, and HOPE there's enough hood clearance.

Problem is, it runs so good now that I hate to screw with it. Not a huge amount of power, but FLAWLESS manners, and no oil consumption on the ~70.000 mile crate engine ('92 Caprice roller-cam, flat-top piston #151 deal.)

Made a mistake with the head castings: bought two PAIR instead of two individual castings. Brand new, still in the double boxes. Anyone want six-bolt Vortec-style heads? Send PM. Price is very advantageous, shipping will somewhat suck.

gmstrong

I can tell you this first hand either get a carb intake with an adapter or leave the stock intake manifold.Very good point about the roller cam.Schurkey why the gmpp?you can get a weiand vortec intake for 160 it will bolt right to vortec heads if do this and a roller cam should pull very strong IF tuned correctly.

Schurkey

Two reasons:

1. I don't have vortec-bolt-pattern heads. I want to retain the Q-jet flange, I want the option of EGR--AND--I want it in a performance-capable package. That leaves one manifold choice that I'm aware of: GMPP 10185063

2. Weiand has gone the low-brow route, their new manifolds are made in China. Weiand can K-M-A on the six o'clock news. At least Edelbrock still casts and machines some stuff in the USA.

thomas1976

The TBI heads like to knock. Best is to get flow matched injectors to not run into unequal cylinder fueling.

Keith5

I'm going to get the Edelbrock 2104 and use an adapter, will I have trouble with my vacuum line for the brake booster?

Schurkey

Summit photo shows a bigass port on #8 runner.

Keith5

The stock manifold has that port too, but it's plugged. GM put a port on the front of the TBI manifold for the brakes. The remote coil looks like it could be in the way of using the port in the back. I was wondering how you all that use the carb manifolds run your vac hose.

gmstrong

drill and tap a hole.

Keith5

I looked through some pictures and it looks like somebody with the same setup just ran a rubber hose around and behind the HEI. I'd rather do that, it would clean up the engine's appearance.