My current powertrain setup is the original block bored and stroked to a 383, carbed, with a forged rotating assembly. Im leaving the city im in within a couple months and im just getting horrible fuel economy with this engine (12 highway) and thats with a t56. I have the 3.42 posi from an 02 camaro ss.

I thought about just getting rid of it to buy something cheaper on gas, but trying to sell it for the last few months and ive never got a single call. The economy is bad where i live so thats why im leaving. Looks like ill have to keep my car, but thats not a bad thing. So i guess the best thing would be to sell the engine i have now and buy something lsx based so ill have some power and good fuel economy. I have a big cowl hood on the car now, but im sure it wouldnt be too hard to swap someone for a stock hood so the car wouldnt look dumb. The car is fast and the engine only has about 1500 miles on it, so i should be able to sell it for a good bit.

Im really thinking about getting an LM7 5.3 327 from a silverado. I loved the one that was in my 05 silverado z71. I actually had the rare edition of the silverado and had the high output 5.3 that was alluminum. Maybe i can find one of those and save some weight. I already have a t56, so i think i would need a new bellhousing input shaft and front plate?

Ive never done an efi swap before, but im sure it wont be too hard considering the engine will be completely stock. But what about the engine itself, the silverados were pretty much ALL autos, how will that work with the manaul tranny? Also im sure there is going to be some kind of security ignition in the pcm also?

Im just looking for some more info! Thanks heres my car now:

 

how about put the car on the dyno and actually tune the jetting to get better mileage? Or buy a wideband and tune it yourself. The library has several books on holley carbs you can take out for free to learn on.

 

Ive thought about it, but ive never been a carb person. Im not sure where i could even find a dyno, ive searched google and nothing.

 

look into innovate motorsports for the wideband and tune it. your mileage will increase.

 

I know i could get better mileage, but not without vacuum advance. I need the limiter plate and the springs for the distributor. The curve isnt right and i get 60 degrees with vacuum advance so ive unhooked it until i could get the kit. Bad thing is summit is out of stock on everything i need and would have to wait till the 28th.. i can wait that long. Also i think the engine is detonating. I cant figure it out. The car violently jerks while cruising, its not a lean condition.. the car is running rich. Its not gearing. The cam isnt that big so im thinking its just detonating but can be to sure because the exhaust is too loud that i can hear the engine. I didnt build it so im not sure on the compression but the guy said it should be 10 5: 1. People have told me that i need to run higher than 93 octane but thats the most i can get where i live.

Thats also another reason im contemplating getting rid of it, it has to use the highest octane out, so when me and my wife leave to travel somewhere else, what do i do if im out of gas and they dont carry 93? Id be screwed right?

 

what kind of distributor do you have. jegs prolly has what you need.

 

Its a cheapo ebay distributor, but since then ive replaced the rotor and cap with msd parts and the coil is an accel super coil. The vacuum canister I have now can adjust when the vacuum advance comes in, but can limit the actual amount because lack of a limter plate. I could just make my own if i can just find where to buy the springs from alone... Does autozone sell them?

 

you know autozone or oreillys may sell the mr gasket advance kit. that might get you by for now.

 

yeah ill check it out. quality really shouldnt matter.. its just springs lol

 

i suppose the only difference in springs is that if you use the crane or msd kits there are articles on here that tell you which ones to use. other than that yes. you need to look at the bushings to.

 

Do you think you can send me a link of the articles?

 

here is one that i have went by. it is very true.

http://www.73-87.com/7387garage/drivetrain/hei.htm

look at the crane advance link
http://www.stevesnovasite.com/forums...ad.php?t=79939

here is another good read
http://www.hotrodders.com/forum/dist...1-a-59033.html

after this last one i did not hook to intake vacuum.