See
http://www.classicinlines.com/HeadSwap.asp
Stock engines were rated gross as less than 90 hp, and I doubt you'd see more than 50 hp at the crossplies with one. So you can only but improve it, and probalby have to.
You can certainly use the later head, but its not a bolt on for the reason stated by the second poster, you can do alater model head swap to a 144, but
you have to plane it the full amount to get the chamber volume from 62 cc to below 52 cc. The 144 ran either a 52 cc head for 7.5:1 compression, or an 8.6:1 compression, 44 cc head. The factory figures were 7.5:1 with 51 cc head and 8.7:1 with 44 cc head. Check with the
http://www.falcon6handbook.com/compcalculator.asp calculator.
Number Of Cylinders
Bore Diameter [3.50 inches]
Stroke Length [2.50 inches]
Combustion Chamber Volume [52 cubic centimeters]
Head Gasket Compressed Thickness [0.025 inches]
Head Gasket Bore Diameter [3.63 inches]
Piston To Deck Clearance [0.025 inches]
Select Piston Type
Dish/Valve Relief/Dome Volume [positive cubic centimeters]
Volumetric Efficiency: 80%
RPM: 4500 rpm
Results:
Displacement, [cubic inches] 144
Displacement, [liters] 2.4
Static compression ratio 8.6:1
Cubic Feet per Minute required @ 4500 rpm, [cfm] 150
Estimated Horsepower @ 4500 rpm
Assumes altitude of sealevel, barometric pressure of 14.696 and 60° air supply to carburator 82 flywheel net hp
The post 1978 heads are very good for flow, but have a poor bathtub chamber which is too big for flow and comopression. When you plane it, all the losses become plusses.
So
1. Plane it 90 thou, and
2.install 62.5 thou hardened washers under the adjustable rocker pedastools, and
3. use the stock 144/170 steel head gasket, and you'll have no problems.
The ealier head flows poorly, but has good compression ratio with a nice, small chamber. The difference between a dog and a success is just 10 cc;s of chamber volume, which should cost you about 60 bucks to correct if everfything else( guides, valve seals, valve seats and the head is crack free)
is good.
What cam and carb you gonna run?
The stock 144 cam is a low tech stump puller with the specs from the first line below. Its a great way to loose 10 hp where as the 200 or 250 cam is 256 degrees and has a lot of lift.
