I finally got a 350 4-bolt main block and am about to start building it. My question is this.... I commute on the interstate daily. Would a mild (325-350 hp) 350 or a 383 be more reliable/ efficient?

 

What is it going into? In a 1T truck, the 383 might be a better choice. In a lighter vehicle, a 350 might do well if there is a lot of stop/start driving.

If you're looking for streetability and mileage, you might want to be thinking about what EFI system you will use.

 

sorry i didn't specify. it will be going in my '86 iroc. as far as the efi goes, it will be tpi still. probably an aftermarket edelbrock setup. at the very least, i'll use the stock one and port it as well as up the injectors. most of my driving will be on the interstate,although in the atlanta area, that sometimes involves a considerable amount of start stop.

 

Dont waste your money on the edelbrock setup. If you're gonna do it go with a short runner design, but as stated you need to decide this BEFORE building the motor. Camshaft, head/valve/rocker/spring/piston selection are all important and somewhat dependant on eachother. Longer duration cams tend to be better with the long tube intake design of the TPI. But if you go with a shorter runner design you'll have more options with reguards to other parts of the motor.


As for reliability between the two, assuming you build them both right they're both great motors. But a 383 on a TPI setup will run out of breath fast above 4500 rpm. but like I said give us more info on which intake system you're looking to use and we'll be able to make better decisions with reguards to your setup.

 

really and truly, i would like to use te stock tpi setup and port it and add bigger injectors. but it's my understanding that it will basically choke my motor.