Can I keep the TBI with a new, bigger engine?

[1976Scottsdale]

I am going to be putting either a 350, 383, or a 454 in my 1987 R-10.  I was wondering what would have to be changed in terms of the computer and efi stuff to accomodate the small block options.  If I go big block I have access to everything as the donor is a running truck that was wrecked.  I would prefer to keep the small block.  Maybe Del can step in here.  He seems to be famous on the site for the 383 engine in his truck.  I was also wondering if I TH350c from an el-camino would work in the truck.  The 700R4 is messed up pretty bad so I am not gonna sink another 1200 into rebuilding it if I dont have to.
My plan is to use my 3970010 "010 020" 4 bolt block and bore it 30 over to fit each piston as tightly as can be allowed and use a set of 041 64cc heads I bought.  I was also thinking of installing either the MTC-1 cam, 204/214 duration, 420/443 lift, or the other one that has like 443/465 lift and roughly the same specs otherwise.  For the intake I would like to use my Performer RPM intake with an adaptor to fit the TBI unit.  I am just throwing that out there, I am a complete novice to fuel injection, just tired of fussing with carbs.

[VileZambonie]

What's in the truck now? Are you saying you would like to keep your existing TBI? Unsure if you have a bb or sb now? You will need a chip for your application. The MTC-1 is too mild if you ask me. It's great for a 305 but if you are going 350 or 383 you need a little more cam. Your second choice or even a little more would be ideal.

I know you don't wanna spend the money but the 700R4 is the way to go. If yours is toasted look for a used one. If you really wanna use the TH350 though you won't have a problem.

[1976Scottsdale]

Sorry, forgot to mention my current setup.  I have a 305 right now, the original with 52000 miles, an open carrier 10 bolt (assuming 28 spline) with 2.56 gears, and a rebuilt 700r4 with 8000 miles on it.  Am going to be buying a set of 3.08 gears once I get the money from a site member here.  I guess the 700 is not dead, it just goes down the road and will act like it is going to kick out of lockup and then slams back in like a split second later.  I heard these had some valve issues, but I talked to the local shop and he said 450 for the valve boldy rebuild and update kit and another 900 to rebuild the rest (No warranty if I don't let him).  My thinking on the 350 lockup trans was that it is basically brand new and was in an 83 el camino with a lopey 350 and we bought it for the motor and the trans was left over... so its free to me if I want to use it.  I also have all the parts to keep from heving to ruin any of my factory shafts or crossmembers.

[VileZambonie]

Why 3.08 gears? Go with at least 3.45

If all that's wrong with your 700r4 is the lockup just unplug the tcc for now.

As far as your TBI set up it will work with a new prom and depending on your engine choice different injectors.

[Captkaos]

You are wasting you time going from 2.56 to 3.08.  There won't be any noticable improvement.

If you go with a BBC I would get the bigger TBI that comes with it.  You will need a prom for changes to anything other than stock.

[1976Scottsdale]

Well I do still have access to a 3.42 posi rearend, would have to swap my 5 lug shfts in but that no big deal.  I was under the impression that unplugging the trans from its wiring would burn it up since it is designed to lock up.

[76_Scottsdale]

It will generate a little more heat and you'll notice it rev a little higher but it should be ok.

[1976Scottsdale]

I could live with that.  Maybe add an extra trans cooler and a temp gauge so I can keep an eye on it.  What it does now is jerk like it would when unlocking for passing gear, but then it goes right back in.  Could the lockup colonoid or wiring be bad in the tranny?  I mean the trans is rebuilt, but the truck is still 21 years old.  I am realistic enough to realize that other things may be wrong outside the tranny.

[eventhorizon66]

Listen to the gearing advice here.  Don't waste money on 3.08 gears (what I have now with my 700R4).  I'm getting 3.73's and a posi here in few days as I can't stand anymore of those gears spoiling my fun.  If you have access to 3.42's for pete's sake go with those.

[Lt.Del]

If you were to go w/ a 383, replacing the 305, you are keeping the small block setup---everything will bolt right up to a 350 or 383 except the starter.  The starter bolt pattern will be off set (diagonal) on a 350/383.  Everyone knows I favor the 383 with an RV type cam.  I was out playing with mine today passing every slow driver out there on the roads--listening to that shortened dual pipes sing their tenor tune.

I agree with the majority about a lower gear.  I have the 350c lockup tanny and It really doesn't benefit me unless I am doing over 60, but, man, after 60, she will take off w/ no effort and bury that speedo in a few seconds.

The drawback here is that I have a 3:08 gear and wish it was closer to a 3:50 or 3:70 range.  I do a lot of city driving and the lockup feature just doesnt' kick in until I am doing almost 40--then it is time to stop for another light.  Man, what a lower gear would do for me!

You have the right ideas coming to ya here.  I am no expert on TBI and don't know what computer chips need to be changed, but, between the Vile and Chris giving you the scoop, you can't go wrong. 
       


March Madness is upon us.  GMU final 4 baby!
 

[VileZambonie]

What it does now is jerk like it would when unlocking for passing gear, but then it goes right back in.  Could the lockup colonoid or wiring be bad in the tranny?  I mean the trans is rebuilt, but the truck is still 21 years old.  I am realistic enough to realize that other things may be wrong outside the tranny.

It doesn't sound like the trans to me...When does it jerk? It sounds like a bad TPS to me.

[1976Scottsdale]

I could see that.  I have a new TPS and a new IAC valve.  I'll try them.  Getting a set of 3.73 gears in a bit.

[Robry 87]

I've just did that type of swop 305 to beef up 350 the TBI is so post to good but i'm not haveing good results yet but i did'nt pick the cam nether so you most likely will have better luck then i have.But i used the same tran's700r and i can only use1,2,3 no over drive at all i have no power but every body here beleaves my problem is in my cam and i have 3.46 gears,but i'm doing a lot of changes this weekend look at my post (IS THIS A GOOD MATCH)to see what all i've done and what im doing maybe it can help you every body here has help me a lot.

[1976Scottsdale]

I rebuilt my TBI unit today and installed and set the TPS and IAC valves as per their instructions.  Had to take the TBI unit off when it got mad and started spraying my coil with fuel, but that is all better now and the truck is not crispy.  This is the best it has ever run.  I won a set of 10 bolt 3.73 gears on ebay last night to put it, but one thing occurs to me.  If I have 2.56 gears now, will 3.73 gears swap in?  Will they If I have 2.73 gears?  Also putting true duals on this weekend.

[Robry 87]

what is the TPI,and ASI and how do i set them that may be my problem with my truck i have a dead spot double peddle to get past it.