I been wonder which is better MPG 346 or 370? I plan to built up for turbo set up. I wonder where I able find new 5.3 block for able to built for 346. Also the 370 too. I need to compare which one make good power and dependable. I like to find which one would be better with mpg. I been research some info about this both. I just like ask around and share with people's opioin. Thanks.

 

Those are two different blocks FYI.

 

The 346 will be lighter on fuel. But I'd go with the 370. Eventhough the 4.8/5.3 block can safely be punched out to 3.898" bore, at least 1 person on here had problems with overheating eventhough apparently the correct machining and sonic testing was done.

 

if ya gonna go that far into the game gas mileage is the lease of your worries

 

You mean I should go 370?

 

I know 346 and 370 are NOT same block. 5.3 block able use 346. 6.0 block will be bored to 370. By the way what do you mean FYI? Also what color you have charcold on your truck. I been look some info for charcold to paint 2 tone on my truck. Can you find a code paint from yours?

 

ls1 block bored to 370/383

 

I will have a 370 here in the next month. FYI is For Your Information.
I thought maybe you already had a block to use.

 

Nooo, Im going keep 5.3 block. I just want to buy a new block and built up. I wasnt sure about 346 or 370. I need to know which one either I able order block real soon! Need get some info about that..


Hey tell me about paint code if you dont mind?

 

When your trying or wanting to make big hp, mileage should not even be a concern.. Hp burns fuel.. The 370 is a bigger engine and will burn more fuel...Unless you have a fuel mileage tune done for it. In that case it would be pointless to have even built a engine for power..