[jago]

Hello, I have been offered a Pair of NEW c27a heads to go with my NEW C27a block I have. However the same person also has:

For sale. Brand new, unused 825 (Honda) engine

Used as a test bench model, its never been in a car and comes complete with all ancilliaries such as starter, distributor etc. Its obviously a rare piece.

Should I get the Heads or the Whole 2.5 engine? Also does anyone have any spec on the 2.5?

 

[sam o nela]

I'd get them both personally...

The 2.5 is a good engine...there are some slight differences from the 2.7 but most obvious is the lack of a Variable Intake Valve plate and the 2.5 uses vacuum advance at the distributor to adjust timing...

 

[sam o nela]

Oh yeah and I forgot to mention that the 2.5 has 10 less hp :lol:

 

[jago]

so i could swap the manifolds (in and ex) over?

ignition would be intresting.

you say 10hp less, over what c27 is that? the cat or not cat?

i might get both just the the intrest in actually seeing a 2.5

 

[sam o nela]

To my knowledge, with or without a cat, the 2.5 always put out 10 less than the 2.7....

That is to say:

Cat- 2.5 = 151 hp and 2.7 = 161
Non Cat = 2.5 = 161 and 2.7 = 171

I believe the main increase was from the butterflies, displacement and different heads...

 

[jago]

so gas flowing the heads adding the inlet tract and, a little more ign advance should see her well then,

i'll be looking at this engine monday night all being well

 

[sam o nela]

Actually I would stick with the 2.5 intake manifold for the time being and see about porting it out as it (anecdotally) flows better than the 2.7 manifold due to the lack of a bypass valve plate....

I'm still trying to get my hands on an extra 2.5 manifold to do a complete comparison...

 

[jago]

had a rough look at the engine. looks ok, dusty but is actually new. was intended for an auto. the intake manifold is way different, biggest things i noted were, design of fuel rail and breather to plenum. the throttle body has somthing sticking out into the moving air. and the ignition has a lot more rom to play (more advance)

i got the heads tonight, got home and opened them up, they are both front heads however one has all valves and exhaust rockers the other has no valves or rockers. still happy as i can play at gas flowing the empty head.