1966 GMC 305 V6 Service

[raylube]

This picture reminds me of your rebuild

[Rufton]

Originally Posted by raylube

This picture reminds me of your rebuild

Wow!
Thanks for that pic.
It made my day!

[TommyDuncan]

I know it's kinda early but I am really curious what kind of mileage you are getting.
Are they really as bad as they say?
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[Rufton]

Originally Posted by TommyDuncan

I know it's kinda early but I am really curious what kind of mileage you are getting.
Are they really as bad as they say?
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I'm very curious about the mileage also. I log mileage every fill. I put smaller main jets in worn out 305E last year and improved hwy mileage from 10 mpg to 12 mpg. The compression was so low and oil consumption so high I was surprised it didn't foul plugs. I hope the fresh 305E will do better. My gear oil in rear and trans may be too heavy for mpg; I'm thinking of switching to lighter gear oil.
I expect initial readings to be low because not fully broken in.

Guess I should road trip to get mpg data faster

[TommyDuncan]

Originally Posted by Rufton

I'm very curious about the mileage also. I log mileage every fill. I put smaller main jets in worn out 305E last year and improved hwy mileage from 10 mpg to 12 mpg. The compression was so low and oil consumption so high I was surprised it didn't foul plugs. I hope the fresh 305E will do better. My gear oil in rear and trans may be too heavy for mpg; I'm thinking of switching to lighter gear oil.
I expect initial readings to be low because not fully broken in.

Guess I should road trip to get mpg data faster

thanks for the reply. What rear end gears are you running?

A friend of mine had one of these and swears he got 7mpg no matter what. He also said it was geared to low for much hwy use. After looking at their low rpm torque curve I wonder if it is necessary to gear them that low?
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[Rufton]

Originally Posted by TommyDuncan

thanks for the reply. What rear end gears are you running?

A friend of mine had one of these and swears he got 7mpg no matter what. He also said it was geared to low for much hwy use. After looking at their low rpm torque curve I wonder if it is necessary to gear them that low?
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Pre 2012:
305E loves 70+ mph cruise
3.07 dana 44
P235/75R 15 28.9"
Stromberg WW 280 CFM 2bbl
Main jets 0.055", 0.054"
Poor compression
high oil consumption
2" single exhaust pipe
quiet muffler
mix 8-9 mpg
70mph hwy 9-10mpg

2012 changes:
Main jets 0.050", .050"
70mph hwy 11-12 mpg


2013 changes:
Main jets 0.050", .050"
305E rebuilt
Good compression
Low oil consumption
mpg to be determined

[TommyDuncan]

Originally Posted by Rufton

Pre 2012:
305E loves 70+ mph cruise
3.07 dana 44
P235/75R 15 28.9"
Stromberg WW 280 CFM 2bbl
Main jets 0.055", 0.054"
Poor compression
high oil consumption
2" single exhaust pipe
quiet muffler
mix 8-9 mpg
70mph hwy 9-10mpg

2012 changes:
Main jets 0.050", .050"
70mph hwy 11-12 mpg


2013 changes:
Main jets 0.050", .050"
305E rebuilt
Good compression
Low oil consumption
mpg to be determined

thank you again!

There is a really clean long bed knee knocker that has been sitting for at least 5 years that I am slowly convincing the owner to sell to me. I wanna like the V6, I really do...
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