Hmmmmmmmmmm

[Slow Guy]

Ok...Buddy of mine has a 620 and is looking at maybe a little more oomph.  Just outta curiosity...can 695 jugs and pistons be bolted onto the cases he has? And if so what else would need to be done to do this.  Thank you for any input.



that is all
nothing follows

[jerryz]

Fast by Ferraci do a big bore kit for the 620

[Monster Dave]

^but it's pretty costly to buy.

[Slow Guy]

aaaaand that would be why i was wondering about the 695 top end.  should be able to find one on ebay for a wee bit cheaper...maybe

[Bladecutter]

Wouldn't an actual 695 engine from eBay just bolt right in?
That might be the cheapest and easiest route, once you get into the whole process of tearing down the motor, and rebuilding, and then having to install a Power Commander to change the fueling needs, anyway.

BC.

[Speeddog]

695 barrels and pistons on a 620 bottom end makes a 750.

However....IIRC, the 695 pistons are taller deck height, so they wouldn't work.

[ducpainter]

695 barrels and pistons on a 620 bottom end makes a 750.

However....IIRC, the 695 pistons are taller deck height, so they wouldn't work.

695 heads also?

Someone has had to have done it. 

[Speeddog]

620 and 750 are the same 61.5mm stroke.
695 is essentially a de-stroked 750, 57.2mm stroke.
IIRC, the rods are the same length, so they got the deck height back by making the 695 pistons taller by ~2.15mm.

Stew and I did an upgrade of complete 695 heads and hi-comp 750 pistons in a carbie 750.
That was a ripsnortin' little motor, really what the 750 should have been to begin with....

The OP's buddy could basically do the same thing, but there may be some cylinder base dowel pin position issues with 695 jugs on a 620 case.

Fueling would need to be worked out with a PCIII or such.

[ducpainter]

gotcha

[Raux]

620 and 750 are the same 61.5mm stroke.
695 is essentially a de-stroked 750, 57.2mm stroke.
IIRC, the rods are the same length, so they got the deck height back by making the 695 pistons taller by ~2.15mm.

Stew and I did an upgrade of complete 695 heads and hi-comp 750 pistons in a carbie 750.
That was a ripsnortin' little motor, really what the 750 should have been to begin with....

The OP's buddy could basically do the same thing, but there may be some cylinder base dowel pin position issues with 695 jugs on a 620 case.

Fueling would need to be worked out with a PCIII or such.

I have a 800 66mm stroke crank I didn't end up using for my 696.

[brad black]

from memory 695 has 800 valves and cams, so they'd be good heads to have.  but they'll also have large combustion chambers so you'll need domed pistons to get the comp back to std even.  normal 750 high comps won't give the advertised comp.

88mm cylinders from 750 or 800 will make it a 750, but you need specific 750 pistons as the piston compression heights vary for different stroke cranks.  620 and 750 are 61.5mm, 800 is 66mm, 695 is 57.2mm.  so 800 pistons are shorter, 695 pistons are longer.

i'd put a 900ssie motor in it.  extra gear, wide ratio gearbox, strong clutch.  no matter what you put in it, it'll always need a little more oomph.