Upgrades to TBI 350

[JBerryhill]

I have an 87 GMC with a stock 350 TBI engine. This is the first TBI engine I've ever had. What performance upgrades can I do to this and still keep the TBI unit ? I want 325+ HP

[VileZambonie]

Heads, headers, bump up the compression ratio, cam, chip

[85MudMonster]

Heads, headers, bump up the compression ratio, cam, chip

Won't the heads do that???


I'm just messin with you...

[VileZambonie]

Not unless the combustion chamber volume decreases

[85MudMonster]

Not unless the combustion chamber volume decreases

Well isn't that the point of new heads anyway.

[JBerryhill]

Will a cam change affect the computer? I know on a 86-87 Mustang with speed density you could change anything except for the cam (It effects the vacuum). If you changed the cam you have to upgrade to mass air flow. Do these TBI setups not work the same way, they are speed density also. If not then can someone suggest a good cam, I prefer low end torque, also are these roller engines? I have a set of 97 Vortec heads already and some Flow Tech headers to install. Thanks for the help again, Jerry

[VileZambonie]

Not unless the combustion chamber volume decreases

Well isn't that the point of new heads anyway.

No

Your TBI is speed density. It's not a roller unless someone changed it. The vortec heads are good but you will need a different intake manifold. This cam will work http://store.summitracing.com/partdetail.asp?part=SUM%2DK1105&autoview=sku

[Captkaos]

You can put just any cam in there it has to be compatible with the ECM unless you put a chip in it.  You are going too have to change a number of things to get to 325+ HP and  cam, heads and a chip are the beginning.

[chevymotocross]

Bringing this thread back, I have an 87 as well but with the little wimpy 305 tbi     Well after a few upgrades... it aint as wimpy. I have true dual 2.25'' exhaust with high flow cats from manifolds back. K&N Filter. Just added a TBI spacer and injector spacer and those made a huge difference. Truck has lots of low end- mid range. Still falls flat on top but that is probably due to the horrible flowing heads and cam these TBI engines have. They make great low-end torque but thats bout it in stock form.

What's left to do? Well, I don't want to mess with cam and heads so I am going to add an adjustable fuel pressure regulator to bump the pressure up a bit, a custom chip and probably a corvette servo and shift kit for firmer shifts from my 700r4.

What else can I do but don't really want to: electric fans, cam, heads, intake manifold, headers, msd ignition, gears..

Speaking of gears, most of these trucks came with 2.73 or 3.08 gears (mine has these). The 3.08's seem decent now with the performance upgrades. Before the upgrades, the truck was a dog. I highly recommend atleast a 3.42.

You can do the cam and head upgrades, you just have to find someone that knows how to burn a chip for what you are wanting to run. I hear tbichips.com does a great job. Stay away from "drop in" chips, you need one made for YOUR APPLICATION.

TBI is choked up pretty badly in stock form, but there are lots of mods you can do. They run efficient and I think are more user friendly than a carb. The biggest issue is finding someone that knows how to burn a good chip for what you are running.

Good Luck!