Wondering if the Trailblazer/Envoy 4.2 litre Vortec 4200 inline-6 will fit in an S-10 Blazer. My 4.3 is fine and should remain fine for a long time, I'm just fantasizing. The 4.2 inline has much more HP and torque. How easy or impossible would this swap be?

 

It's not a practical idea. The 4.2L I6 is almost twice the length of the 4.3L V6.

 

Exactly. Itwon't fit.

5.3, or even the 4.8 is a much better way to go for an engine swap.

350 works too.

 

agreed with rriddle3 way to long. 350 swap is a very comman thing and are easy to work on

 

That would be nice that 4.2L I-6 is a nice running engine. But they had to redesign the whole truck for that engine. I saw an S10 at a car show last week with a SBC in it. Nice fit. They had headers on it & did away with the fan & clutch in favor of electric fans. You really have to look to see it is a V8.
An a V8 in the Blazer should give an increase of gas mileage. If set up stock with fuel injection I would bet on 25-30 MPG if you drove it normal. This is only a guess if someone has one please correct me.

 

I think we're alllooking for thatV8.

 

Probably a max of 27 MPG taking it easy on the highway...

With factory rubber, mine hit 24 MPG.

Around city, you'd only see a 2 - 3 MPG increase at most (which is a LOT for these things, lol)

 

Yeah I thought it might be too long. 350 it will probably be then! I like the Mustang 4.6 (don't worry I'd never put a Ford engine in it). The 4.6 gets mid 20's in gas mileage while driving it pretty hard, and it's a fun engine. Plus for once it's a Ford engine without tons of problems. I don't think there's a GM V8 that's that powerful and fuel efficient at the same time (though I hope there is, any suggestions?). My dad clocked his 4.6 Mustang at 22MPG at 95MPH. I want something like that from GM.

 

You getbetter gas mileage in the city!?!?

Well, come to think of it, (depending on what time and which highway I'm on, I would actually get better City MPG than Hwy MPG... Standstill-Traffic for the lose