Turbocharging a 250

  • Thread starter Thread starter Anonymous
  • Start date Start date
sefus":15semqgq said:
so what would be a good carb choice for a blow thru set up? (im guessing these are 4bbl choices right?)
The Holley mechanical secondary 4150 4-bbl is the almost universal choice for a blow-thru. I'd guess a 650 CFM for a 200 CID engine, or a 750 CFM for a 250 CID engine.
 
Hey, any ideas on how much one of those 4barrels would run,a nd where to get one? Also, how would I put it on my log head, adapter or what? I want to run blow through definitely so I need ideas on carb. Lemme know!
Matt
 
I would call Autozone/Checker/PepBoys for a rebuilt carb. They deal in volume and their prices are generally about as good as you'll see. If you want/need a more cutting edge solution, try Demon Carbs.
 
shutters at demon carbs

so which of those two would be good for the 200 block with (us)250 head?
and has anyone got a really successful 4bbl adaptor templet made up?
 
I've done the 231 Buick Turbo onto a 250 Chevy and it worked fine. That was several years ago and it's still running great up in Ohio. I hear from the guy that bought it, now and then.

I wish we had of installed a water injection unit on it so we could have cranked the boost up, it's only running 5psi.

We used the entire turbo unit, Qjet carb and all. I didn't even have to touch the carb settings, it was close enough.

Ebay no# 2445968019 is were you will find another complete unit, there is 5 days left.

BTY: The 250 Chevy was completely stock but it sure didn't feel like it. :D

John
 
^^what you do about the mechanical fuel pump that gn's have? im guessing just found a electric that was close in pressure.
 
If it's a draw through style like the early Buick, you do nothing. It will supply more than enough fuel.

If it's a blow through style then you have to Boost Reference the pump. There is a small hole in the top of the pump that allows air into the dry side of the diaphram area. You have to drill it out a little larger and tap it to accept a small nipple. A hose is attached to the nipple and to the intake manifold. That way as the boost goes up, so does the fuel pressure.

With EFI there is a fuel regulator that you can buy that can be boost referenced. It is sold by a dozen different companies mainly the supercharger manufacturers. It's fairly priced but you can find them on Ebay real cheap. :D

John
 
Got my rebuilt Q-jet today. It's the Buick turbo part number so it has the power system that's referenced to manifold vacuum/pressure. Plan to put a small check valve between manifold and carb so it'll read vacuum in the manifold, but not boost. I know from nothing about Q-jets, so I thought a professionally remanufactured one was best for me.

For a JY DIY project, it's getting expensive. Ordered an MSD 6-BTM yesterday. That's about all the hardware.

Now it's mock up time and fabricating some brackets and pipes.

I'll do pictures as I go.

Wish someone built an aluminum sheetmetal rocker cover for the 200. Looks like you could make the sides straight with welded in tubes for bolts. Make it a bit higher so it would clear everything--roller rockers, etc. You'd think I haven't spent enough money as it is.
 
Back
Top