EFI Upgrade

[88EXi]

Has anyone done an EFI upgrade on a early model (68) block? I am thinking of going with the Edelbrock EFI system. I was hoping with a good porting job and free flowing exhaust I would improve my mileage. I also will be installing a 700r4 with the overdrive. Any ideas?

[Genopsyde]

i say go for it. i may do the same down the road too.

[89Firebird2.8]

I saw one of those systems on Powerblock once. I think it was on 'Musclecar', but I might be wrong. Anyways, they put it on a 69 Charger, and it looked pretty straightforward. I think it's a couple grand though, isn't it?

[Morley]

You could put in a GM TPI set up cheaper and it is closed loop. Make sure if you buy an after market EFI that it is a closed loop, feedback system.

[GreyGoose006]

the first problem with gm tpi is that it barely flows enough for a performance oriented 305. if you try to put it on a 350, you will have an engine that makes ungodly torque from idle to 2500 rpms and falls on its face at 3500 rpms.


get a holly super ram. its closed loop and doesnt have the sudden fall off of the gm tpi.
the t in tpi means tuned, which means that the runners are tuned to provide power at a certain point. when the 305 tpi was introduced, the idea was to give the 305 the same low end torque as the 350.

if it were me, id go with a super ram, the runners arent tuned to provide any certain boost anywhere, just better performace everywhere.

[Morley]

I disagree. The TPI is just fine on the stock 350's of the time (245-250 HP) and with a little work can and do support higher HP levels.
Even if you were to go with the stealth ram you'd want to start off with the GM harness/ECM and other accessories. If you buy the entire S/R from Holley it is going to set you back almost 3k.

[GreyGoose006]

well if you factor in the fact that the ported slp runners are 600, the matching plenum is another 400 or so, the intake is like 400, you need injectors, fuel rails, ect.
and at the end of the day, you wont make power above 4000 rpms.
look, if you want the best possible solution, go with the holly.
if you want to compromise the the gm tpi is for you.
im serious about the 350 being too much of an engine.
the system was designed for a 305 making 170 hp
what do you THINK will happen when you put it on a 350 and expect it to make 260 hp.
and thats with a stock engine.
people claim to run tpi's up to 400 hp, but i think that is bull.
my engine claimed to make 400 hp, but i dont really believe it.
as soon as i can afford it, im getting a stealth ram.
ill be selling my tpi so if you want it, make me an offer when the time comes.

[88EXi]

I talking about a Pontiac block not Chevy so how does an TPI fit on a Pontiac block?

[MrPbody]

"Fit" the Pontiac? It doesn't... Holley "ProJection" works okay up to about 550 HP, but after that, it can't provide enough fuel. A couple of our customers have tried. Ron's Racing Products in Tucson has "The Flying Toilet", which DOES work well, but BIG bucks. When "tuning" the Pontiac, 400 or larger, treat it like a big block for fuel and chassis requirements. A common misconception about it is the small block stuff is adequate. It's not.

There are couple of dedicated websites for Pontiacs, but we're not allowed to list them here. PM me and I can point you to guys that do this stuff with the old Injun.

Jim

[Morley]

Originally Posted by GreyGoose006

, im getting a stealth ram.
.

I've known a few people that went to the SR, they didn't make a substantial increase in power when they did the swap.
I'll be sticking with MY 400 hp TPI (not stock). It pulls just fine up to about 5500 RPM. And lets face it, unless you are a regular track runner, that is more than enough RPM. For street driving you'll hardly ever see anything aboue about 4500 RPM anyway, and you want your power production to be in the lower RPM's anyway.

[GreyGoose006]

true, but as soon as you start talking about ported heads, you are talking about a high performance engine.
add to that the desire for good gas mileage, and the TPI quickly becomes the stopper in the system.

the tpi is good for smaller V8 engines.
a TPI would be ideal on a chevy 302 or 283.
they are smaller displacement and could benifit from the extra torque the TPI helps generate, and wouldnt likely out flow the TPI.
bigger engines (especially power oriented engines) actually loose power with aTPI and loosing power is the same as loosing economy. either way, you arent as efficient as possible.

[Genopsyde]

that's true, if you leave the tpi stock. but most ppl upgrade the tpi when the upgrade the engine. same as when ppl put a bigger carb when they upgrade the motor on older cars.

[Morley]

Originally Posted by GreyGoose006

.
a TPI would be ideal on a chevy 302 or 283.

No it wouldn't. Those engines are higher reving than the 305/350's and TPI does not like to rev high (stock).