New Guy delving into the world of TBI tuning

[SierraTom]

Thanks for the add here, looks like I've found the right place! '87 GMC R2500 Pickup 305/400 working on swap to 350/700r4 have everything that goes with it computer, harness etc. 350 is a very low mile #880 Vortec era shortblock which I'm assuming was a crate replacement having no numbers and has fuel pump provision, have a pair of fresh rebuilt to stock 062 Vortec heads but I do have a set of Beehive springs, Comp Retainers and Jegs 3/8 screw in rocker studs. Also have Jegs carb to vortec intake, fabbing a TBI adapter plate. Truck is a daily driver just looking for some good performance, still need to decide on a cam like to go roller. Looking forward to learning my way around Tunerpro. Any advice will be appreciated, Thanks again Tom

[Fast355]

Keep the 400! Much better transmission for what you are planning. 700r4 with any kind of power is a ticking time bomb especially in a heavy truck.

[buddrow]

I have to agree with Fast355. Ive been in the transmission industry for 20 years, and while those trucks came with the 700R4, it's only because they didn't have another option for an overdrive trans, at least not for another year or so. With that said, another caveat of the 700r4 is T.V. cable adjustment. With the aftermarket intake, your factory throttle cable bracket may not mount in the proper location for correct cable geometry, leading to a burnt up trans or uncomfortable shifts, or any of a myriad of other shifting/pressure concerns. The TH400 is a much more reliable transmission, due in part to its simplistic design compared to the 700r4, only needing a vacuum signal from the engine to determine shift pressure.

Buddrow

[SierraTom]

Yes Sir the keyword is planning, still weighing my options. No doubt the T400 is better suited for a performance build, 300 HP is about what I'm shooting for but don't get me wrong HP doesn't mean squat it's the torque curve I would be more concerned with so until my money tree blooms again there's still some time for planning and learning what I can about tuning ! Thanks Tom

[SierraTom]

Just thought I would also mention that I have a couple extra TBI units to play with and welding, machining and fab (makin stuff work!) is not a problem here.