Polishing combustion chamber

[Weekend Racer]

Is there any gain of polishing combustion chamber? polishing take off some metal = make conbustion chamber bigger =lower compression ratio!
Thank,

[Dan Fahey]

Originally Posted by Weekend Racer

Is there any gain of polishing combustion chamber? polishing take off some metal = make conbustion chamber bigger =lower compression ratio!
Thank,

I port and polish Iron LT-1 heads based on Joe Mondellos recommendations.
My Heads made our PINKS ImpalaSS run 8 tenths quicker.

Smooth sharp edges, can reconfigure to make chamber smoother
Open up back side of Intake Chamber. Polish with flapper paper..
Will increase 1 or 2 cc but can be recovered with a little milling of the head.

Benefit with polishing, will help prevent pre-ignition, better breathing will help HP.

Dan

[eddie c]

All of that info is correct,but none of it is allowed in stock class and I also believe its not allowed in superstock class either. ed

[mannymen]

fire away in SS

[Weekend Racer]

Thank! for your input guys,
Dan, Is it a back a back test ,.08 seem a big improvement ?

Very interesting)))

[Dan Fahey]

Originally Posted by Weekend Racer

Thank! for your input guys,
Dan, Is it a back a back test ,.08 seem a big improvement ?

Very interesting)))

YES..surprisingly it was and with the same cam.
The WAIL Impala Club PINKS car started with a 383 which blew up at Beaver Springs.
A junk yard 350 was put together with the 383 cam and began running a lot of 12.20's.
More tuning and they ran 12 teens at Capitol in very hot summer heat, best was 12.11.

The engine lost oil pressure at Englishtown.
Fred Diven and Chris built another engine with their fixed up Aluminum Heads.
The car now runs 12.80's good weather, in hot weather runs 12.90's.
Using hot weather comparisons, 08 sounds may sound like a stretch but I witnessed it.

Got my heads back but the lost oil pressure tore up the valve guides and valves.
New Valve Guides, 2.02's/1.60 valves, matched the bowls, reworked the Chamber a little bit.
Not had a chance to test these.

The PINKS Heads used 1.94 and 1.50 high flow valves.
Before I made one cut I contacted Joe Mondello and had a good talk.
Triggered by reading his articles on porting Oldmobile Heads.
Then with his information bought his best porting kit and followed his simple instructions.
Had no access to a Flow Bench but used a piece of String to test flow.
A year later he later wrote an article on porting Vortex and LT1 Heads.

Here is a tip:
Joe recommends the 1.94 Intake for SBC 350's up to 368 cuin
For real good improvement upgraded to a 1.60 Exhaust.

Sure would like to put my work up against ported GM LT1 Aluminum Heads.

Dan

[engineguy]

Originally Posted by eddie c

All of that info is correct,but none of it is allowed in stock class and I also believe its not allowed in superstock class either. ed

"Grinding and polishing in combustion chamber premitted" in NHRA Super Stock classes, per rule book.
"Combustion chamber modifications prohibited" in NHRA Stock classes.