Can someone suggest a cyl head porter in
Norcal who has experience with the big port
990's? I'm looking for a little more out of the
LS6 in a 18' jet, Thanks in advance.........
Can someone suggest a cyl head porter in
Norcal who has experience with the big port
990's? I'm looking for a little more out of the
LS6 in a 18' jet, Thanks in advance.........
For all your norcal Horsepower needs...
http://www.v-drivevideo.com/jerrysga...ey_Grose~0.jpg
I have a guy who is top notch with big block chevy motors, and works magic with the grinder...30+ years porting and building motors.
He is in the north bay - PM me for contact info, I don't want to just post it up.
In the Bay Area you can give Gromm Racing Heads a call they are in San Jose (408) 287-1301
For all your norcal Horsepower needs...
http://www.v-drivevideo.com/jerrysga...ey_Grose~0.jpg
Kick azz work out of that shop
SWEET!!! I'll make some phone calls. Do these people mainly
do street cars & do any of them maybe specialize in marine
combos or? I know these 990's are pretty big and I've seen
in some chevy books they have been made to flow pretty good.
Im just wondering the difference between porting & a new set?
some other suggestions as well:
I agree with earlier post,Gromm Racing Heads off of Coleman by the Airport; very happy with past work
and
Morgans machine Shop in Walnut Creek...Tim Morgan little pricy but lots of experience 925-939-7346. He just did some 088's for me and I am looking forward to running my deep v.
good luck
personally, if I was to do it again, I would go with alum, AFR or Edel....good porting on cast iron heads from my experience is not cheap.
Before you spend a bunch of money on those 990s PM Steelcomp, he has/had a set of Rher Morrison Brodex II heads quite reasonable...Check the spam section and search "Brodex"...............MP
Why spend money on ancient designs? RHS, Merlin, Dart, etc... all produce cast iron heads that are superior right out of the box and have lots of potential from hi-perf to all out race. You can get them bare, complete, whatever. Check out the RHS website before you decide, then call someone like Grose for an opinion on the cost vs benefit. Besides, engine builders always have something laying around on the shelf for a bargain.
For what you're doing, your 990's will work just fine. You don't need to have them ported, but here's what you can do to really step them up.
1) have 2.25 intakes installed. The bowls are too big with the 2.19's and you can't get a decent valve job. the 2.25's will allow a nice 3 or even 4 angle valve job, and that right there will pick up flow tremendously.
2) The valve job...get a good quality performance valve job on both int. and ex.
3) Good valves with undercut stems, or have 11/32" liners installed and use 11/32" valve stems. Have the intake valves cut with a 28* backcut about .025-.030 wide. A good quality stainless valve like a Manley Pro Flow (or Severe Duty if you're running a roller) is worth the investment.
4) A little unshrouding in the chamber, mainly around the intake, will make a big difference. CC the chambers, as well...get them all equal.
5) blend the bowls under the valves. A quality bowl blend is 90% or what you're looking for.
Any decent performance shop will be able to do these things for you, and it shouldn't cost you any where near what a port job will. The ports on the 990's are borderline too big for a 454 in a jet boat, so you certainly don't want them any bigger. With the mods I mentioned, you'll have a really nice set of heads that can support plenty of power.
Lastly, take the $$ you were going to spend on porting, and have the heads flowed, then contact Chris Straub with all your engine details, and have a cam made for exactly what you're building. You can have all the porting in the world, but without the right cam, it's a waste of time, and you aren't going to find one off the shelf that's going to be exactly right. I can't emphasize this enough!! Have the heads assembled with the right springs, at the right seat pressure, with some quality Chromoly or Ti reatiners and hardened locks, and you'll have a nicer set of heads than most out there.
Good luck.
Posting Permissions
Reply With Quote