Hello. I have a '92 Chev 350 1/2 ton reg cab/longbox, 2wd. I was going to upgrade to GM's Vortec Heads, Edelbrocks MPFI that bolts up to the heads(still uses the stock tbi unit less the injector assembly, and uses the stock computer but with an edelbrock chip or a custom chip), right now is what i have: Compcams 252H, 252/252 ADVERTISED,(206/206@0.050", 0.453"/0.453" lift w/1.6:1 rockers and 110 lobe separation), Gibson shorty headers, stock 3" single exhaust(less the convertor), open k&n, TnT riser plate, 700-r4 rebuilt to corvette specs w/B&M shifter kit and open 3.42 diff(soon to have an Auburn locker), AND STILL THE STOCK CHIP! i fiqured that i still get around that 22-23 mpg yet and ran the truck for 30,000 km like this and no problems. But my question is this.. do you think that i should gain lots more power with the heads and gain a more broad torque curve with the MPFI that will give me better or the same fuel mileage? See this trucks used for everyday but when i punch it i want that ****er to go! Thanks for your time.

 

How much of a difference did you notice with the mods you've all ready done?

 

Hello. With the mods i have done now.. i have noticed a really good gain in power. My 0-60 time in this configuration was around 8.2-8.5 seconds.. which for a truck is not toooo bad. But i feel with the heads and the multiport it will drop me 1 or more seconds... i hope. My friends 91 gmc shortbox had the same config with the exception of the Edelbrock performer heads and he dropped from 8.4 down to 7.2 0-60 times.. just with the addition of the heads. So im hoping for the good results too. Im not trying to turn this thing into a dragster but turning it into a truck thats fun to drive, gets good mileage, and can be used everyday with no problems. I just want power to be there when i want it for fun or work.

 

That will work very well for you. Nice cam choice, too.

EDIT: oops, you should try a dual pattern cam, like the XE250 or XE256, as Vortec heads (and most others, really) like a little more exhaust duration to clean ou the cylinder... You can get by with your cam for sure, though. just a little more efficient with the dual pattern.

Edelbrock will help you, too, if you need it.

I have actually toyed with doing a similar conversion myself for my Hot Cam use but with a Weiand taller single plane manifold but I really like how it's running now. Why screw with 313hp 350cid and a XE250 mellow cam and 400+lb-ft of torque TBI with a crab manifold/adapter, yah know???

[This message has been edited by FastBroker (edited April 02, 2001).]

 

Hello. Does anyone think that because there is no injector assembly blocking the air flow somewhat and with an individual injector at each cylinder... will the 1 11/16" bore provide enough air for naturally aspirated up to 300 - 350hp? I was planning to put a supercharger on it and getting around the 350-400hp and then i dont think that a 2" bore even then would be necessary. What do you think?

 

I'd use 2" w/blower. 1-11/16" should be ok to make 310-330hp with the edelbrock MPFI kit and XE256 cam and MAJOR PROM WORK... The PROM that edelbrock give you is pretty good, though, and they have a bin for AL heads that is awesome for iron heads. Has a lot of timing but it is emmisions timing and works pretty well for iron heads without emmission concerns.