Howdy Back David:
We made an aluminum adapter from scrap. I wasn't aware of any commercial adapters at that time. I think Mike carries an adapter at CI. Most any competent machine shop could do the work required. The shop I used here in Idaho Falls is no longer in business, but Troy's Machine shop in Rigby, Idaho is who I'd use today. Troy now has a CNC machine that can mill just about anything out of aluminum.
I uses the intake valves from a 144 six, which measure 1.467",for exhaust valves. I was not aware of SSI, 1.5" exhasut valves at that time. CI has them for you and they are a worthwhile upgrade when you're doing your head.
Look for a '78 - '83 head D7xx and later. These heads are on both 200 & 250 engines these years. What year is your 250 engine? With a stock cam 9:1 is a good goal CR. If you upgrade to a longer duration cam you may want to shoot for 9.2:1 at your elevation. I'm running about 9.75:1 here at 5,000 ft. elevation, but have to use an ocassional fill of 91 octane gas in the heat of the summer. Your cost estimate seems reasonable to me based on eastern Idaho prices, I don't know about your area, but if you do a little shopping and can find a shop that likes the idea of what you want to do, and is willing to work with you, you'll do better. I had the shop clean and inspect the head before I started. They did the major mods for the 2V carb adapter and cut the preliminary valve seat and told me to not touch that area. Then I took the head and went about cleaning up the ports, polishing the chambers, fitting the exhaust port divider. Then the head went back to the shop where they milled it, finished a three angle valve seat, back-cut the intakes and installed the valves. Then I took it to balance the chamber volumes, clean and paint it. The point is, how much of this work can you do/are you willing and able to do?
FYI- the albatros of the 250 engine is the huge deck clearance of the pistons. If/when you do the block, I hope you seriously consider addressing this problem. My 250 block had a deck clearance of .150"!!!! That is not untypical of a 250 engine. There are several ways to address this, but that's another post. And we've got to stop hijacking Ralf's thread.
Adios, David
David
Aplogies to Ralf.
My 250 is from a 1970 Mustang. It had the head off supposedly for a valve job so probably has thicker head gasket on it. Seems to run very well although had a rear main leak which seems to have stopped with STP. For this vehicle a worthwhile upgrade from the 200.
My plan is to get a head from the year vehicle you mentioned, get these mods done and find a 2100 Autolite. Then hopefully a quick swap so I have little down time.
I know you mention Troy in your book, I should check shipping charges to his shop. The machine shop in town has no experience milling these heads for a 2v adapter although they could handle the valve job. I could probably do the work you did on your head with help from mechanic friends. We have a barter system based on beer.
Also thanks for the info on 1.5" valves and the sequence of the individual tasks on your head modifications.
My elevation is 4200 with frequent trips down as far as sea level and higher as well with passes through mountains. Running ocassional mid grade and premium tanks are no problem.
My goal is to have a spare motor on hand should the current one develop a major problem and have to come out. At this time I could address the deck clearance problem, upgrade the cam and so on.
Thanks for your help.
David
We made an aluminum adapter from scrap. I wasn't aware of any commercial adapters at that time. I think Mike carries an adapter at CI. Most any competent machine shop could do the work required. The shop I used here in Idaho Falls is no longer in business, but Troy's Machine shop in Rigby, Idaho is who I'd use today. Troy now has a CNC machine that can mill just about anything out of aluminum.
I uses the intake valves from a 144 six, which measure 1.467",for exhaust valves. I was not aware of SSI, 1.5" exhasut valves at that time. CI has them for you and they are a worthwhile upgrade when you're doing your head.
Look for a '78 - '83 head D7xx and later. These heads are on both 200 & 250 engines these years. What year is your 250 engine? With a stock cam 9:1 is a good goal CR. If you upgrade to a longer duration cam you may want to shoot for 9.2:1 at your elevation. I'm running about 9.75:1 here at 5,000 ft. elevation, but have to use an ocassional fill of 91 octane gas in the heat of the summer. Your cost estimate seems reasonable to me based on eastern Idaho prices, I don't know about your area, but if you do a little shopping and can find a shop that likes the idea of what you want to do, and is willing to work with you, you'll do better. I had the shop clean and inspect the head before I started. They did the major mods for the 2V carb adapter and cut the preliminary valve seat and told me to not touch that area. Then I took the head and went about cleaning up the ports, polishing the chambers, fitting the exhaust port divider. Then the head went back to the shop where they milled it, finished a three angle valve seat, back-cut the intakes and installed the valves. Then I took it to balance the chamber volumes, clean and paint it. The point is, how much of this work can you do/are you willing and able to do?
FYI- the albatros of the 250 engine is the huge deck clearance of the pistons. If/when you do the block, I hope you seriously consider addressing this problem. My 250 block had a deck clearance of .150"!!!! That is not untypical of a 250 engine. There are several ways to address this, but that's another post. And we've got to stop hijacking Ralf's thread.
Adios, David
David
Aplogies to Ralf.
My 250 is from a 1970 Mustang. It had the head off supposedly for a valve job so probably has thicker head gasket on it. Seems to run very well although had a rear main leak which seems to have stopped with STP. For this vehicle a worthwhile upgrade from the 200.
My plan is to get a head from the year vehicle you mentioned, get these mods done and find a 2100 Autolite. Then hopefully a quick swap so I have little down time.
I know you mention Troy in your book, I should check shipping charges to his shop. The machine shop in town has no experience milling these heads for a 2v adapter although they could handle the valve job. I could probably do the work you did on your head with help from mechanic friends. We have a barter system based on beer.
Also thanks for the info on 1.5" valves and the sequence of the individual tasks on your head modifications.
My elevation is 4200 with frequent trips down as far as sea level and higher as well with passes through mountains. Running ocassional mid grade and premium tanks are no problem.
My goal is to have a spare motor on hand should the current one develop a major problem and have to come out. At this time I could address the deck clearance problem, upgrade the cam and so on.
Thanks for your help.
David