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C15_Sierra · 04-10-2011, 07:25 PM

I need some opinions on my motor swap. I want to get rid of the 305 and put something in that has power, reliability, and a good sound. Since I'm emissions-exempt, anything goes. I want to run full-length headers, and a true dual exhaust, dumping just after rear wheels.

The two options I'm considering:

Built 350 or 383: I want to run a fuel injection setup on this motor, so I'd prefer to swap in a Vortec 350/383. My boss runs a 383 w/ Vortec heads in his 1970 C10 and I love everything about that motor: the sound, power, and since it has a TBI setup, it starts up and runs great. The cost would be greater to swap and build just the motor than a stock LS swap (see below), but I wouldn't run into the exhaust and AC compressor clearance issues that seem to plague most LS swaps. Plus its the classic SBC, and that should count for something, right? I could use my TH350 for the time being, and swap to a 700R4 at a later date (friend of a friend owns a transmission shop and can hook me up)

Vortec 5.3/4L60E: I priced out a 5.3/4L60E from LKQ at $1400, and will see if I can get a little lower than that. Looks promising with 300 hp out of the gate, but I'd have to reprogram the computer (not a big deal), buy new motor mounts (again no biggie), and fab a new transmission crossmember. The biggest worries are the AC compressor and exhaust clearances, since my friend is running into those issues on his '84 GMC LS1 swap. I'd like to keep my factory AC so there would be some conversion issues with the LS swap that I wouldn't run into with a SBC swap. I also don't like that I'd have to run a electric-to-mechanical speedo conversion box to keep my mechanical speedo, but hey theres no free lunch

. I do like that its a modern drivetrain in a classic wrapper, and again since I'm looking for high streetability, that works well w/ my vision. Theres an '04 Silverado at work with over 230K that runs well and gets over 20 MPG on the highway, so I know my money would be well spent with an LS swap.

What do you guys think/do you have any insight into how I should approach my decision?

04-10-2011, 07:25 PM	#3
C15_Sierra Registered User Join Date: Apr 2011 Location: Hartford CT Posts: 223	Motor swap opinions I need some opinions on my motor swap. I want to get rid of the 305 and put something in that has power, reliability, and a good sound. Since I'm emissions-exempt, anything goes. I want to run full-length headers, and a true dual exhaust, dumping just after rear wheels. The two options I'm considering: Built 350 or 383: I want to run a fuel injection setup on this motor, so I'd prefer to swap in a Vortec 350/383. My boss runs a 383 w/ Vortec heads in his 1970 C10 and I love everything about that motor: the sound, power, and since it has a TBI setup, it starts up and runs great. The cost would be greater to swap and build just the motor than a stock LS swap (see below), but I wouldn't run into the exhaust and AC compressor clearance issues that seem to plague most LS swaps. Plus its the classic SBC, and that should count for something, right? I could use my TH350 for the time being, and swap to a 700R4 at a later date (friend of a friend owns a transmission shop and can hook me up) Vortec 5.3/4L60E: I priced out a 5.3/4L60E from LKQ at $1400, and will see if I can get a little lower than that. Looks promising with 300 hp out of the gate, but I'd have to reprogram the computer (not a big deal), buy new motor mounts (again no biggie), and fab a new transmission crossmember. The biggest worries are the AC compressor and exhaust clearances, since my friend is running into those issues on his '84 GMC LS1 swap. I'd like to keep my factory AC so there would be some conversion issues with the LS swap that I wouldn't run into with a SBC swap. I also don't like that I'd have to run a electric-to-mechanical speedo conversion box to keep my mechanical speedo, but hey theres no free lunch . I do like that its a modern drivetrain in a classic wrapper, and again since I'm looking for high streetability, that works well w/ my vision. Theres an '04 Silverado at work with over 230K that runs well and gets over 20 MPG on the highway, so I know my money would be well spent with an LS swap. What do you guys think/do you have any insight into how I should approach my decision?