350 econo build

[dq409]

As most of you know I now have this 84` 2wd Blazer ripe for a V8 trans plant.

The idea is to install a nice running 350 that is built for everyday driving not for racing.

So that being said I am now collecting parts for the build.
What I want to achieve is a good running SBC that has the best gas mileage possible.

These V6`s suck when it comes to mileage and power and I believe the V8 should deliver several more MPG.

I can only squeeze about 14.5 MPG with this V6 and figure a good built V8 should get 16 or better with the smaller S10.

The easy way to go would be a carburated 350 but do know that an injected one should deliver better mileage.

Any ideas on what the best build would be?

Things to figure would be commpression, heads, intake manifold/carb and cam.
I also have a 700R for the trans.

Going with injection would require installing/wiring computer control for the injection as 84 was non-computerized.

I would prefer injection and know there are kits and info out there on doing this.

All ideas and suggestions are welcome. ,,,dq

 

[Fathead Racing]

I once put an injected 350 in an 84 K 10 4X4. Lot's of hoops to jump through. Speed sensors, brake peddle disconnect lot's of wireing. It can be done and the payoff is a great running 350 that does deliver better gas milage. If your in a hurry go for the carb. The injected 350 needs to have "ALL" the bells and whistles hooked up or the swap is not worth it. But very doable!

 

[1961BelAir427]

as long as you've been doing this......how much old 283 stuff do you have laying around?? For milege, it'd be tough to beat in that light blazer. I wouldn't go looking for one, but I figure you may already have a few. As far as EFI....the easiest and cheapest way to go is to nab a TBI setup from the junkyard.

Since they built millions of TBI equipped S10's and Blazers it shouldn't be hard to find. You can use the gas tank and fuel pump from a later model. Everything from a 4.3L version should work fine. All you'd need to change would be to get a V8 TBI intake, injectors, and computer chip. You could get the 350 stuff from a fullsize truck or if you go 283, you can use 305 parts and it'd run pretty good. Don't plan on TBI if you want a performance cam unless you plan on having a chip burned for it...and then you better be careful what you use. Headers and exhaust improvements do wonders for helping gas milege. About the only HP improvers that do. If you prefer manifolds, 82-92 camaro and firebird ones fit well. Not many others do. The TPI powered cars have the best manifolds.... 2 1/4" outlets I think. I hope this helps ya some.

 

[jr.W]

DQ check out this site there is a lot of info both performance and mileage.

http://www.gofastnews.com/board/technical-articles/75-100-mpg-carb-does-really-exist.html

http://www.gofastnews.com/board/engine-technology/225-faucet-screen-carb-booster.html

 

[dq409]

I know the "hoops" thing already as a good friend has put a TPI in his S-10.
I was looking more for info on the internals of a MPG build.

I`ll look around net for more info.
From those "links" it looks like the best way to go is injected to get the best atomization of the fuel for mileage.

I`ll also have to pester the "Whiz kid" that setup the TPI in the S10. ,,,dq

 

[1961BelAir427]

Oh if you are thinking of a TPI install... the milege should be great. I got a best of 26 MPG with a 350 TPI in a 89 formula (auto/3.27:1 gears). Before the headers and exhaust work it only got 23 though. Of course airodynamics had alot to do with it I'm sure.
Starting from scratch I'd use a late model block, flattops pistons, decent factory iron heads with small 64cc chambers, and all the factory hyd roller cam equipment. Too be honest I can't think of much to improve on the factory 350 TPI. As far as the camshaft itself......pick up a stock LT1 cam from a 94 - 97 F-body. The duration is short, but the lift is a little better than the TPI cams. Think somewhere in around 200 degrees at .050" and .450" lift on wide 114 to 117 lobe centers. Not exact specs, just off the top of my head. The best TPI cam was the 89 model which was 207/213 - .415"/.430" on a 116 LSA. The LT1 cams should be easy to find and dirt cheap if not free since all the F-body people are swapping to aftermarket stuff. This should help low-end TQ and milege some. Vortec heads might also help due to better combustion, but the needed intake will set ya back $400 and I don't know that the improvement in gas milege would add up. They are worth a good 25HP or more too.

 

[oldskydog]

I've got a TPI set up from a 97 Astrovan 4.3 if you want to experiment with your v6. I also have a 350 TBI intake and a few TBI's if I didn't sell them all at the last swap meet....can't remember.

 

[dq409]

I've got a TPI set up from a 97 Astrovan 4.3 if you want to experiment with your v6. I also have a 350 TBI intake and a few TBI's if I didn't sell them all at the last swap meet....can't remember.

Thanks guys,,, The V-6 is out,,, never seen one get any kind of good milage.
I`m still gathering parts so I`ll let you know.
I have a set of reconditioned SBC heads promised from a friend so I`ll wait and see if they are the small CC`s . (says they are)

I almost said heck with it and thought to go the easy route and install the carbed version.
Might have to do that anyway with the plan on adding the TPI as the money allows.
I could do the internals now with carb and add the TPI later.,, dq

 

[1961BelAir427]

I still strongly recommend going with a factory Hyd roller block. They are cheap and plentiful so even if you already have an older 350, you won't be out much to make the switch.

 

[jr.W]

And if you go hyd roller block no more worries about flat cams. From what i am told
most of the fi motors have zero cyl wear so less machine cost.

 

[1961BelAir427]

Oh yeah I forgot about that point. I believe the lower RPM all these newer engines live at due to the overdrives has as much to do with it as the EFI and fuel distribution (ring wash).

 

[dq409]

I still strongly recommend going with a factory Hyd roller block. They are cheap and plentiful so even if you already have an older 350, you won't be out much to make the switch.

OK,, I`ll add that to the list,,,,