Replacing the TBI engine, suggested upgrades or changes?

[1STLS1]

I decided to install a TBI 5.7 LO5 Goodwrench crate motor I pulled from another vehicle in my '87 K10 with a tired 5.0 TBI. It ran and drove well so it should be just plug and play. My goals are reliability, drivability, fuel economy, and towing. I don't see a reason for it to ever be over 5k rpm and would need it to pass local emissions which is a dyno test and verify the evaporation system isn't leaking. An issue I currently have is I am running 33" tires vs the factory 31" with the factory 3:73 ratio and at 45 mph, it's in and out of lock up. It's annoying, I am hoping the additional torque will make it less of an issue as I am not going to swap gears.

The block has the ability to use a factory roller cam but currently has flat tappets in it. Is it worth it to put a mild roller cam in it? A more aggressive flat tappet cam? Adding an intake? TBI mods like salad bowls and injector spacers? Any other suggestions?

Thanks!

 

[Edelbrock]

Assuming the motor has some miles on it, I would focus on getting it tuned up as much as possible and leak-free before installing. Maybe a new fuel injector, premium plugs and wires, cap, rotor, etc. So before trying to go above what the original factory performance is, get it back to original performance as a starting point. If you lost 10% power due to old worn parts, then restoring that 10% with a tune up is far easier and cheaper than gaining 10% with a new style cam, and these expensive upgrades can never be truly utilized if the engine is not in tip top shape tune up wise. Maybe you already did that stuff, but if not, then these steps may help you or someone else reading this.

 

[1STLS1]

Assuming the motor has some miles on it, I would focus on getting it tuned up as much as possible and leak-free before installing. Maybe a new fuel injector, premium plugs and wires, cap, rotor, etc. So before trying to go above what the original factory performance is, get it back to original performance as a starting point. If you lost 10% power due to old worn parts, then restoring that 10% with a tune up is far easier and cheaper than gaining 10% with a new style cam, and these expensive upgrades can never be truly utilized if the engine is not in tip top shape tune up wise. Maybe you already did that stuff, but if not, then these steps may help you or someone else reading this.

I agree with you but the engine was in great shape to begin with, it only had 10K miles after it was installed before the truck body rusted away from the CA coast, dealer maintained with new distributor and rebuilt throttle body weeks before they gave up on it. I have new AC Delco tune up stuff along with alternator, starter, sensors, hoses, belts, etc. I am not afraid spending a couple bucks to do it right because I only want to do it once. When I finish, I only want to open the hood for oil changes for the next couple years

 

[gmbellew]

grab the PROM from the 5.7. you will need it. I also assume you are using the TBI from the 350 with the 350 injectors? I think 305 and 350 trucks used the same ECM, just different PROMs.

I'd keep the 350 stock cam. straying too far results in the need to get a custom tune.

 

[Slooptin]

If your block has the bosses for the roller lifter retainer spider in the valley, you can upgrade to a roller cam. I pulled almost everything I needed from a junkyard motor (cam retainer, spider, dog bones) and ordered new lifters, new double roller timing set, and a stock vortec 350 cam from rockauto. Only thing I had to really work to find was the melonized distributor gear (only because dizzy shafts vary in size so you have to measure what you've got). No tune and it ran great until I took it off the road for some repairs a few months ago. I'm ~$400 into it and I probably could have done it cheaper if I snagged everything but the dizzy gear and a new timing chain from the junkyard.