Piston cut outs?
Piston cut outs?
Author
Discussion

MPO

Original Poster:

264 posts

134 months

Sunday 25th October 2015
quotequote all
Piston cut outs?

Interesting one…

Do we need piston cut outs because of bigger valve diameters (Big Valve Heads) and/or to allow for increased cam lift?


MPO

macdeb

8,720 posts

277 months

Monday 26th October 2015
quotequote all
Sort of both and for cam duration.

MPO

Original Poster:

264 posts

134 months

Monday 26th October 2015
quotequote all
macdeb said:
Sort of both and for cam duration.
so, do all 400 HC's and 4.3's have piston cut outs?

There were some 4.3's that didn't have Big Valves but did these ones have large enough cams to justify the cut outs?


MPO



carsy

3,019 posts

187 months

Monday 26th October 2015
quotequote all
All 4.3`s have the cut outs. Big valve or not.

Sardonicus

19,295 posts

243 months

Tuesday 27th October 2015
quotequote all
macdeb said:
Sort of both and for cam duration.
< This, the 4.0 HC has the eyebrows but runs stock RV8 valve sizes

MPO

Original Poster:

264 posts

134 months

Monday 9th November 2015
quotequote all
So, with two piston cut outs per cylinder what increase on cc are we looking at?

MPO

Boosted LS1

21,200 posts

282 months

Monday 9th November 2015
quotequote all
A cc per cut out appx, maybe a little more but I doubt it'll be very much.

Sardonicus

19,295 posts

243 months

Monday 9th November 2015
quotequote all
Boosted LS1 said:
A cc per cut out appx, maybe a little more but I doubt it'll be very much.
Yeh I would estimate 2-3cc per pot