New motor build

Moderator: Mod Squad

Registered User
Posts: 42
Joined: Wed Nov 11, 2015 8:56 am
Location: Houston, TX

New motor build

Post #1 by ssg66stang » Mon Dec 18, 2017 11:43 am

I posted this on another part of this website but was told I might have better luck here getting ideas and advice from people that have the here goes.

So, I was able to come across a 1968 200 cid block with a 1978 250 head for a new motor build that I want to begin. Eventually I plan on using a VI head but for now the 250 head will have to do. I want to either turbo charge or supercharge the motor, nothing too radical but I would like a nice clean setup with good power.(not sure what kind of power is realistic to expect from one of these builds) I know that you can spend $1000's and get crazy power but my pockets aren't that deep. I was thinking somewhere in the $2500-3000 range (not including the VI head). I have done some basic research on the topics but I was hoping that someone on here with actual experience could give me the pros/cons of each setup and some good recommendations on the type of parts that will hold up to the added boost.

I plan on taking my time with the build so once the block is machined, I'm going to start from the bottom-up so the first parts that I think I should be looking for are - crank, cam (no sure what type of profile would be best), pistons, rods. How much should I have the blocked bored? What CR should I be at for either setup? Is 250rwhp realistic with the car being very reliable?

Thanks in advance!

Registered User
Posts: 2429
Joined: Tue Aug 06, 2013 12:33 am
Location: Columbus, Indiana

Re: New motor build

Post #2 by pmuller9 » Mon Dec 18, 2017 12:19 pm

If you look through the Dyno Room tech section you will note that it takes a considerable amount of boost even with the big valve 250 head to make around 250 RWH. See Dyno#1
Those boost levels require an intercooler whether using a turbo or supercharger.

The old paxton ball drive unit is used because they aren't very expensive (If you find one).
The problem is they are only good for 7 lbs of boost.
A properly sized newer Paxton, Vortech or Procharger will break your budget.

The roots style Eaton units used on most OEM engines can be found at a low price but mounting and driving those superchargers can be a challenge although it has been done.

The turbocharging is still the preferred method to provide boost and power.
For a given engine power level, turbocharging produces the least amount of stress on the engine of all other methods including NA.
When set up correctly it is the most efficienct system because it recycles some of the exhaust energy back into the engine system that normally would have been wasted.

User avatar
Registered User
Posts: 4124
Joined: Sat Oct 24, 2009 9:51 am
Location: Lawrence Swamp, S. Amherst, MA

superc? turbo?

Post #3 by chad » Tue Jan 02, 2018 9:02 am

powerband has alot of pic on his several set-ups.
He'd accept a PM if ur willing.
"Big thing is only make one change at a time. Change 2 or more things at a time it becomes difficult to figure which change helped or hurt" turbo2256b » 1/16/2017
Chad - '70 LUEB on '77 frame (i.e. PS, D44, trapezoidal BB 9", 4.11), 250, NV 3550 & DSII to B transplanted, "T" D20/PTO, 2" SL, 1" BL, 4 discs, 33"X15", etc. Seeking: Hydraulic gear motor for Koenig pto. (413) 259-1749

Who is online

Users browsing this forum: No registered users and 5 guests