Where is the data showing grooves in a head make any improvement. Oh never mind, we have been through that discussion 8 friggin thousand times.

I think you are making a huge assumption that a groove is "a good thing"

Mark Steilow had his Camaro on Power Tour. He has an LS7 in it. He shaved the head and it's running 12:1. I know Mark and I know his good friend Jody, who was also driving the car. No issues running pump gas.

The chamber looks like a work of art.



On a similar Dart head I cut one groove in each chamber to direct squish
flow high into the roof of the chamber.

are the grooves just cut in with a swiss file? or is there some sort of complicated tooling involved

To automotive breath:

No, I don't have LS 7 engine yet.

Even if I did, I would want to run it stock (at least till the warranty runs out) for two reasons:

1. This way, I won't have to worry about voiding warranty.

2. Also, it will give me enough time/opportunity to evaluate the stock LS 7 performance/mpg so that I can use it as a base to judge if the groove will make a difference.


To some of you:


Sorry if I caused you unnecessary aggravagtions.

I had no idea that Somender Singh's groove would create so much controversy.

P.S. Yes, the groove is beautiful looking.

What would you do if a crack formed along one of those grooves and ended up trashing one (or both) of those expensive CNC machined heads?

milleldai,
I cut the grooves with a 1/16" ball end mill parallel with the deck surface. I
then widen (to 1/8") and deepen the opening into the chamber roof with a
hand held file.

Red Grant,
One of my many current projects is to modify a Chevy 5.3L truck engine for
reductions in fuel consumption and emissions. I know someone that grooved
a stock truck with outstanding results. Keep in touch and I'll let you know
how it goes. I hope you get your LS7, it is an awesome performance engine.

I don't mean to hi-jack but I'm considering doing this to my 383 that has yet to be assembled. I have a set of 906 vortecs that I will running on this engine. the compression will be right around 11:1. Now Im thinking of a two groove setup with the grooves aimed at the spark plug with the grooves making about a 60* angle to each other. This engine is planned to be a mostly street engine I'm looking for a little cushion zone to run pump gas without pulling tons of timing.

what are your thoughts?

oh and some specs
.535/.540 lift
242/252@.050
300/310 advertised
113 lobe separation
106 intake centerline

pistons are flattops

Your combination is ideal for the modification for two reasons. The camshaft
overlap causes reversion and excessive exhaust residual gas in the chamber
at low RPM. In addition 11:1 compression is pushing the limits with a 23
degree iron head engine.

With the grooves you will find a much improved idle quality and outstanding
off idle throttle response. These circuits will be much easer to tune with no
need for over rich mixture to mask poor combustion. This alone will result in
a reduction in fuel consumption. No choke is needed and warm up time is
reduced to little or nothing. Spark plugs and oil will run noticeably cleaner.

I have been doing numerous heads with a two groove layout like in the first
picture, it works great. With your combination I would consider a third groove
similar to the pent roof head shown.

So with you suggestions I drew up a rough sketch of my heads with three grooves let me know your opinions on the placement of the grooves
these heads were last on a 400 so ignore the endings of the lines.

Perfect, Just make sure you don't run into the valve seat especially on
the intake side it comes close to the deck.

How deep do you recommend to cut? approximately 1/16?

The deck on the Vortec heads are very thin, 1/16" deep is good, thats
how deep I go with the thin deck. Here's a set I did for a 4x4 truck.

WOW! those heads are worked over. Thank you very much for your advice I really appreciate it. lets hope she will run on pump gas

Good luck with the build. Three grooves will help with the high compression,
keep the ignition advance down at first and run it a little on the fat side until
you get a feel for what it likes.

I'm running these heads on a 11:1 compression 383, 10.90s at 3500 LBS on
pump gas. It has about 10 degrees more duration @ 0.050" that yours. I can
bump the timing above 40 degrees total with no signs of detonation.

I think your groove layout is best, I try lots of things to try to find something
better.