im swapping my 305 tbi for a GMPP 350 330/HO and im keeping the throttle body injection. But im wondering how to go about it.

ive been told i could keep my stock throttle body and just put 454 injectors and a regulator and a gauge on it.

Or i could go with the HOllley 670 cfm.

Or i could go with a throttle body from cfm. tech. with all in all ends up being close to 200 dollars more than the holley.

one question will the GM injectors fit in the holley throttle body?
and will the aftermarket throttle bodys mount onto the GM vortec tbi intake manifold?

Im just want the best system that will work the best for the longest even if it costs a little more.

Also whats the best place to go for the chip?

 

can anyone give me any ideas
i just talked to the guy from holley and he told me that the holley 502-6 throttle body will only support 275 HP, and GM injectors wont fit into the holley throttle body.

So where does that leave me, i could really use some help.

 

I keep seeing 454 TBI bases on ebay for about $100.00 and they are brand new. Use your current pod, a GM 30 psi regulator, and your stock injectors. The 454 TBI will easily feed 350+ HP then.

 

they have a comple remanufactured 454 TBI, injectors and regulator and everything and the guy said he would even modify the linkage on the throttle body so it will fit my 700r4. He wants 475.00
does that sound like a good deal?

 

I'm running the Holley tbi base with an L05 injector pod with #61 lb/hr injectors at 30 psi. I ran the older style holley injectors on a C1500 for a little while, but the injectors kept going bad on me. I think they've switched to a different style injector and pod on their newer tbi products, but I'm not certain. The gm injector pod can be adapted to the holley tbi base, but it takes a little work. For the gasket to seal between the pod and the base, a little bit of filler metal needs to be added. A friend of mine who can tig weld aluminum filled the spot in for me and I filed it into shape. I've attached a pic at the bottom. I machined the bottom of the pod flat as well. You also have to tap the base to accept the "crooked" style air cleaner hold down. I forget the size, but if I remember right, it's fine thread. I ended up making a block off plate and gasket for where the stock fuel pressure regulator goes and plumbing in an external one that is vacuum referenced so I can run a little less pressure at idle. I picked up the adapter fittings from Earl's Indy to convert the fittings that go into the pod to -6 AN and used a Fuelab regulator on the return line. My engine put out 360 hp on the dyno with a demon 750 and a vortec super victor intake. For hood clearance reasons, I had to run a crusader marine manifold (basically the GM tbi vortec manifold), with 2" bores. I've only made pulls up to 5k with the new engine in the car, but it pulls nicely. I'm going to put a wide band on it before I try to tune it any higher. When I do (should be in the next couple of weeks), I'll let you know if my injectors keep up on the top end. I've run the numbers, and with 61# injectors (rated at 11psi) running at 30psi with a BSFC of .5 lbs/(hp*hr) and a duty cycle of 85%, the injectors should be good for 340 hp.

The throttle linkage connect right up, but I did have to buy a pigtail for the different style of throttle position sensor that the holley base uses. I bought the pig tale through napa. It was from a 1990 C1500 with the L05 engine.