peckm888

i heard you can put a 20r head on a 22r engine and it will boost the compression a bit. my truck is running off propane and i wanted to know if a 20r head swap would help my power? i already put 4:88s on it but the power is still low. the guy who installed my propane kit said a 20r head would give me 50+ horses. what do you think?

874runner

well first of all ive never even heard of someone running a 22r off propane before thats new to me lol second of all the 20r doesnt have more power then the 22r i wouldnt think. or are they both 2.4 liters?

DudeBud

he's talking about the head not the whole motor.


i cant remember what size the 20r combustion chambers are, but most of the power you will gain is due to the intake ports. it will be up in the higher RPM range not to good for wheeling

yotaman

You need to visit http://board.marlincrawler.com/ for that kind of information. There's a few guys other there that have done what you're talking about.

A 20R head and 22R block propane'd with a turbo would be sweet.

idayota

there have been a few write ups on swapping the 20r head onto a 22r block...but lke yotaman says, there are more write ups on marlins board. as far as i understand it the 20r head has two advantages: (1) its valves are larger and they flow better and (2) the deck height is shorter so it slightly increases the compression. hope this helps.

CC_yota

From what I've been reading the valves are actually smaller but the head flows better, OS valves are recommended, and the combustion chamber is smaller which increases compression. That combo will probably work well with propane since it has a high octane rating.

ExB16ner

what is the desired compression for propane?