rover 3.9v8 with 3.5 heads

binv8 · Post by **binv8** » Thu Jan 21, 2010 1:19 am

hi my first post here i have a land rover wich has a 3.9 botem end with 3.5 heads its got a piper cam but is still running the 3,5 injection would i be better of fitting a set of 3.9 heads and injectin system or leve as is would like to get as much power as i can as running 37 inch tyres so need some power in it many thanks

kiwicar · Post by **kiwicar** » Thu Jan 21, 2010 7:14 am

If the 3.5 heads came off anything post SD1 then they are basically the same heads as the 3.9 if they were originally with comp gaskets they are skimmed about 20 thou at the factory but still the same head casting. if they are P5 or P6 heads (which are junk) then swap in the 3.9s.
if the injections are both hotwire then leave as is, if the 3.5 is a flapper type then it may be worth swapping in the hotwire off the 3.9 (that is if the 3.9 is hotwire), though there is debate here on which is best

.
I think you mey be looking for a bit more torque and some stronger drive shafts with 37" wheels.
Best regards
Mike

topcatcustom · Post by **topcatcustom** » Thu Jan 21, 2010 9:09 am

If its a 3.9 block (heads are as good as the same) then fit the 3.9 injection too, if you are taking the heads off you could take a very small amount of material out too which will see you more power as there are a couple of choked places in these heads. Apart from that, unless you want to modify cam etc etc then try and get back power lost over the years, Ramon has a very good page on his site about it here: http://www.vintagemodelairplane.com/pag ... wer01.html