There is one for sale in my neighborhood. It is a cargo van - still empty - but has the hard to find 6 cyl 235 and a 4 speed manual tranny for $500. The present owner says it gets 15-20 mpg city/hwy. My guess is that was correct when it was new Is this a durable engine/tranny combo?

It seems to run all right - smooth and clutch,etc works well - but I would like to spend some time on it to make it more economical and dependable - to make it my land yacht that I can use to tour the country.

What ways would you suggest to peak this up a bit? Are there alternative ignitions? headers? intake manifolds? carburetion? I will check the compress first but the engine is very smooth running, so am guessing there will probably not be any major issues with the block.

Is it possible to get 22 mpg on a van like this? Would it help to lower it 1/2" to 1"?

 

It's 26 years old and still running good! Isn't it?

 

I'm sure you mean a 225. Not a 235. Right?

235 was a Chevy motor from '52 to '62. "Blue Flame Six" '52-'53 235's, was powerglide only. The manual trans motor was a babbit main, splash oil sys 216ci.
'54 on, either, auto or manual trans, had a full insert bearings, high oil pressure.

First year for the 225 slant 6 was in 1960. Virgle Exner styled Forward Look. First motor to receive a alternator.

I saw, and have a picture here in this infernal machine someplace of a prototype slant 6 DIESEL. Ma MoPar was delevoping a diesel to aid the 1 ton pick-up. Dodge didn't have a big block anymore to compete with the 460 Ford and 454 GM The 360 just didn't get it.

Too many smog poloution devices is what killed the slant 6 in the early 90's
You want 20+ mpg in a vehicle that is as areodaymic as a brick, is fairly easy.
One part is going to be hard to find.

Take ALL of the poloution devices completely off the motor. Every piece of vacume, spark contoll, AIR pump, thermostatic controlled vacume switches, vacume amplifier, EVERYTHING!
Headers will help on preformacne, but, hinder all out mpg. Good Turbo or low restrictive muffler will work good.
Get a mid '60's or 1970 intake and carb. (this is going the be the hardest to find) '71 started the downfall. Stay away from '71 and newer.
Use your '82 exhaust manifold. Has more provisions to heat the fuel air mixture than the early exhaust manifold.

You will have to 'play' with your timing, got get as much advance as you can with out pinging. Have problems eliminating the 'ping' or spark knock, go with a 180 T'stat You might loose 2 or 4 TENTHS of a gallon mileage.

If you got some deep pockets, Check Jeggs/Summit, someplace like that for a throttlebody fuel injection. That alone will get you in the 20's mpg

Good Luck