HT 383 mileage

[wyattearp]

Anyone done the HT383 swap and what kind of gas mileage are they getting? With 35" or 37" tires?

 

[nsxxtreme]

Anyone done the HT383 swap and what kind of gas mileage are they getting? With 35" or 37" tires?

I didn't do the HT383 swap. But I did build a 383 with edelbrock aluminum heads lunati cam. I also have the bored out BB 54mm TBI. Fairly sure I have more power then the HT383. I have 35" tires and 5.13 gears and a 700r4 transmission. I get about 8.6 mpg towing a 4k lbs boat. Your mileage may vary

 

[Snoozer]

A buddy of mine swapped one into his '72 K5. He's getting 10-12 mpg with 35" MTR/K tires and 3.73 gears (city/hwy mix). Holley Street Avenger carb.

He's got a really light right foot though.

 

[cuervo]

A buddy of mine swapped one into his '72 K5. He's getting 10-12 mpg with 35" MTR/K tires and 3.73 gears (city/hwy mix). Holley Street Avenger carb.

He's got a really light right foot though.

That's about what I get out of mine even in a 91 suburban. I am running 35s with 4.56s. I got 13 once out of tank but I was purposely light footing it the entire time.

 

[Keitha]

I get about 9 commuting with lots of stop and go.
I get close to 13 on long stretches of highway.

 

[cuervo]

I get about 9 commuting with lots of stop and go.
I get close to 13 on long stretches of highway.

How are you smogging the HT383 in a 91 out in Cali?

 

[K85 Octane]

How are you smogging the HT383 in a 91 out in Cali?

same way I smog my 400, it runs clean enough and looks the part

 

[Keitha]

How are you smogging the HT383 in a 91 out in Cali?

No problem with mine. For all intents and purposes it is an original block etc. and runs clean.

I should have clearified: I do not have the HT383, just a machine shop 383

 

[K85 Octane]

yeah, I think the worst part about an HT383 for smog purposes is the none EGR intake manifold (last I checked)

 

[cuervo]

No problem with mine. For all intents and purposes it is an original block etc. and runs clean.

I should have clearified: I do not have the HT383, just a machine shop 383

Did you do anything to the fuel system and burn a new chip for it?

yeah, I think the worst part about an HT383 for smog purposes is the none EGR intake manifold (last I checked)

GM makes a manifold for a TBI with an EGR port on it. I block it off on my install.

 

[Keitha]

Did you do anything to the fuel system and burn a new chip for it?

I learned to program and burn my own chips, so yes.
I also have a bored out TBI, Edelbrock intake, salad bowl under my air cleaner, and pushed up the fuel pressure.

 

[cuervo]

I learned to program and burn my own chips, so yes.
I also have a bored out TBI, Edelbrock intake, salad bowl under my air cleaner, and pushed up the fuel pressure.

That's awesome. It is a great accomplishment to learn to do it.