I have a 1987 Chevrolet Silverado with a 305 TBI engine. I was considering a 330 HP crate 350 with 64cc Vortec cylinder heads (part number 12486041). Can anyone tell me what kind power that engine would make if it was TBI equipped with a Gm Performance Parts Vortec TBI intake manifold (part number 12496821)? Would that make a good combination?- If not what are some good combinations- cams, heads, etc...Thanks.

This is a good and common swap. The engine with the stock TBI will probably run a little short of the advertised 330 hp simply because the 305/350 TBI only passes about 500 cfm on a good day. So if you want to punch up the top end you need to look into having your existing TBI bored out to a 2 inch throttle with new injectors  see these guys  

http://www.turbocity.com/   . Or you can shop a GM 454 TBI from a wrecking yard, or go with the Holley 502-6 

http://www.holley.com/HiOctn/ProdLine/Products/FMS/FMSFI/FMSFI.html    . Any of these solutions will give you an intake of about 670 cfm which is plenty to reach the full 330 hp of the crate engine your looking at.

You will need a new chip for the computer with a new fuel map. This is especially important if you live where the vehicle is emission inspected, because the cam in the 330 hp engine is a bit long. The overlap period is where the big risk is, as a countinous flow injection like TBI (and most TPI prior to 1996 for that matter), like a carburetor, allow fuel to pass through the intake into the exhaust without burning. This causes your unburnt HCs go skyrocket. So it's important to get the fuel curve spot-on. Try these people

http://www.fastchip.com/

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http://www.hypertech-inc.com/

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http://www.jetchip.com/

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http://www.kcspeed.com/

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http://www.superchips.com/

I've had the best luck with Ed Wright at Fastchip. Jet does a good job when they put their mind to it, but they're mostly interested in precanned production effort rather than the once in a while custom guy.

You'll also have to work the EGR issue as the Vortec engine does not cross exhust under the intake, thus your existing EGR valve has nothing to connect to. The two most common solutions is to use the GM 96 up Vortec exhaust manifolds and related hardware pieces for the EGR as the factory did it or go to Edlebrock who has a header kit for this mod. See them at

http://www.edelbrock.com/

Come on back with further questions.

Bogie

Thanks for the help.  So, will the chip have to be custom made to handle the cam? About the EGR issue, what does the Edelbrock header kit you are speaking of  consist of-- is it just headers for the 96-98 Vortec heads?  

You need a custom chip, the vendor needs all the engine specs going, they are not cheap $300 or so. Any significant changes afterward +,- 10% power change requires a new chip.

You either need the Edlebrock headers of GM Vortec manifolds and the GM Vortec kit for installing the EGR. The Edlebrock web site should have the details.

Bogie

I got the 330 hp Vortec 350 for my 1994 chevy 4x4 silverado. I did get the Turbo city package and the new exhaust manifold for the egr. It seems to lag somewhat. I wasn't sure what to set the timing at so I set it at 0º like I would for the stock setup. Should I advance it a little. It pings slightly when you get on it. It runs pretty good. not as good as I think it should for a 330 hp engine. I am running a performance Cat converter and a flowmaster exhaust. Sounds mean!  I would appreciate any tech advice you can give.  

First question is did you get a new chip blown to the exact specifications of this engine?

If the engine pings a little, more advance will only make it ping more.

If your not running premium fuel, give some a try see if helps knock the ping down, if it does you can push the advance forward a bit. But remember the advance curve is in the computer. Go for a 180 degree thermostat if you haven't already. Also, be aware that you can often hear a mild ping when running headers, not a concern if it's a soft sound only under acceleration.

It sounds to me that the mixture may be to the lean side of normal, this could be the chip, or it could be that it needs a little more fuel pressure. I recommend adding an adjustable pressure regulator and a gauge. Than add a 1/2 pound and see how it reacts, if your alreading running a custom chip; otherwise start with the chip.

Bogie

Bogie

Hey oldBogie, I appreciate your feedback. Since I first posted my question, I found out on the internet  that the timing should be 10º btdc. I adjusted accordingly and WOW what a difference. It idles smoother runs a hell of alot better and has more low end pull. I think that was the trick. I have been running a bit warm (190-200). I think I'll put in a cooler thermostat. Thanks. I am enjoying the power that I couldn't afford as a kid!!!  

The fact that you had the timing at 0 will make an engine run hot, it should be running cooler at 10 advanced, yes?  

I hear ya; my wife has yet to figure out that when I stop working on the same problems I was working on at 18 (faster car/bike, cold beer, a compliant woman) you can just screw into the back yard.

Bogie

It's kinda fun now, I have stickers in my rear window, K&N, Edelbrock, Flowmaster, Chevrolet High performance .etc. I get kids revving up at the stoplights. I run them sometimes. I blew away a Mustang 5.0 the other day. My truck looks clean, kind of like a family truck, but it has a hell of a bite now. I was considering going with a  cold air intake system for it.  Any suggestions?  How much would a lift kit affect my torque to the rear wheels?. I kinda got the fever now, I'm sure you can understand where I'm coming from!  

You really should leave the thermostat at 190 degrees as entire computer system is designed for this operation temp.If you change to cooler temp stat it fools computer into thinking engine is still cold and can cause fuel enrichment problems.  

180 on a Chevy is fine, the computer shuts off cold start enrichment at 167 F.

Remember that oil temps are normally about 20-30 degrees hotter than engine temp. Without an oil cooler a 190 thermostat has the oil at 210 220 the factory 210 has oil at 230-240 and these are just putting around temps, it gets worse if the engine has to work. The former is iffy and the latter is on the line for mineral based oil.

Synthetics can be a solution here, to buy some more operating oil temp space and are really required along with an oil cooler if your going to push the engine either in competition, high speed highway driving or on long hill/mountain grades or the absolute worst, stop and go on a hot day.

The other issue is preignition and detonation. These distructive events are related to end burn temps in the combustion chamber. Years ago before emission considerations, end burn was largly controlled by running the mixture rich and using the fuel's heat of evaporation to "air-condition" the chamber. These days with right-on mixtures, there's no space to cool the charge by evaporation. There are 3 basic ways of managing end burn temps: 1) lower overall engine operating temperature. 2) lower intake air temp by using a cold air source to supply the engine with air from somewhere other than under the hood. 3) water or water alcohol injection, this had its days of popularity but seems to be rather ignored currently.

One must remember that todays high operating temperatures are established by the factory not because they're good for the engine or its oil, nor do they reduce emissions, but rather are needed to meet federal fuel mileage requirements. The factory is pushing these engines as hard as they can to get good fuel mileage through thermal efficiency, this has many risks to the structure and well being of the engine. and if your reading into this that this issue is way more complicated than what you see here, your right.

Way back in the 1930s and 40s the Army Air Corps (predecessor to the USAF) tried very hard to run aircraft engines at 300 F coolant temps to improve thermal efficiency, thus range. With materials far superioer to those found in todays auto engines, they couldn't get there.

Bogie