which heads??

ctrain22 · May 17th, 2009, 11:40 AM

I just picked two 455 motors to put in my 68 442 project. They both need rebiuild, but curious about the heads, and which set to use. One set is "G" cating and the other is "K". Whicg head is better. Plan on mild street build for daily driver, nothing more than a mild cam and headers.

442Harv · May 17th, 2009, 01:57 PM

Their both good heads. G,s are 71, so have harden seats. K,s are W30 replacement heads, and use on a lot of boats. K ,s may have the larger valves? If they need new valves you can put in larger valves.,in either.I would probaby use the K. But if you want to sell a set, you could go with the G,s as the K,s may be easier to sell, and bring a little more money.

joe_padavano · May 17th, 2009, 07:18 PM

Quote:

Originally Posted by 442Harv

...K,s are W30 replacement heads...

Well, not quite. By the mid-1970s, the only heads in the Olds parts system were J and K castings. K heads superceded all the performance head applications, J heads superceded all other applications. Saying that K heads are W-30 replacement heads is like saying that J heads were replacements for C heads. They were the best available at the time, not necessarily exact replacements.

2blu442 · May 17th, 2009, 07:45 PM

The Ka will have 2.07 intake valves. The G may have either the 2.00 or 2.07 intakes. But you can cut out the small valve head seats and have the larger ones installed as Harv said. Depends on what your plans are for head work. I'd be comfortable with either one, but believe the larger intake valves would breath a little better. John

ctrain22 · May 20th, 2009, 05:56 PM

Is there really a difference between the G & GA or K & KA heads? These are GA and KA.

chris83 · May 20th, 2009, 06:15 PM

i would go with the g heads but if you can find a set of big valve c heads you will have more power than you can handle make sure they are the big valve and not the small valve heads you wont be disappointed

Warhead · May 21st, 2009, 04:26 PM

Purchase a brand spankin new set of big valves, and have your machinist correctly install them in whatever set you think will look better on the car. They will flow almost exactly the same as the other, and be within 2% of the C heads (no porting).
Get 2.125 intakes, 1.625 exhausts for max power.
See my response on ROP concerning spring seat depths.
JMGDO
Jim

ctrain22 · May 24th, 2009, 05:17 PM

I am leaning towards using the KA heads, but I think I read somehwere about the exhaust crossover needs to be blocked? Can someone enlighten me on this issue. Boy, this is not like chevy where you only had to deal with round or rectangle heads. Do the GA heads have the same characteristic? If the GA heads have the big valves (which I suspect they do), would they be a better bet. This is not going to be a drag car, just good street performance driver.

joe_padavano · May 24th, 2009, 07:24 PM

Quote:

Originally Posted by ctrain22

I am leaning towards using the KA heads, but I think I read somehwere about the exhaust crossover needs to be blocked?

No more so than on any other Olds head. If you are not planning on an ultimate performance race car, don't worry about the crossover.

Warhead · May 25th, 2009, 08:43 AM

Quote:

Originally Posted by ctrain22

I am leaning towards using the KA heads, but I think I read somehwere about the exhaust crossover needs to be blocked? Can someone enlighten me on this issue. Boy, this is not like chevy where you only had to deal with round or rectangle heads. Do the GA heads have the same characteristic? If the GA heads have the big valves (which I suspect they do), would they be a better bet. This is not going to be a drag car, just good street performance driver.

MUCH easier than the BB Chevy.
You forgot to mention closed/semi/open chamber BBC heads.

Other than valve sizes, and spring seat depths, these heads are pretty much identical. Measure the valves to be sure.
Pull out the set that will be the easiest to lift (it just does not matter), and take them to the machine shop for a standard rebuild. You will be happy with the performance, because they will be going on a 455. You don't have to do anything else.

64Rocket · May 26th, 2009, 07:02 PM

Just as has been said, for a daily driver any of the heads will do. The valve size will not make any difference. For a cruzier, troling the streets, long drives in the evening, after you close the hood no body can tell the difference.
Flip the coin and pick which ever.

Gene

csouth · May 27th, 2009, 11:49 AM

Not trying to hijack the thread, but since you guys were on BB I thought I'd ask. I know a guy selling a 455 with J heads for @ $400. I did hear that these were restrictive and should be avoided. I know its a newb quest, but are engines these even worth buying?

May 17th, 2009, 11:40 AM	#1 (permalink)
ctrain22 Registered User Join Date: Oct 2008 Location: Ventura, CA Posts: 141	which heads?? I just picked two 455 motors to put in my 68 442 project. They both need rebiuild, but curious about the heads, and which set to use. One set is "G" cating and the other is "K". Whicg head is better. Plan on mild street build for daily driver, nothing more than a mild cam and headers. __________________ 68 442 Convertible

May 17th, 2009, 07:45 PM	#4 (permalink)
2blu442 Moderator Join Date: Sep 2006 Location: Medford, Oregon Posts: 2,256	The Ka will have 2.07 intake valves. The G may have either the 2.00 or 2.07 intakes. But you can cut out the small valve head seats and have the larger ones installed as Harv said. Depends on what your plans are for head work. I'd be comfortable with either one, but believe the larger intake valves would breath a little better. John __________________ 1964 Cutlass Factory 4spd 1965 442 4spd 1967 442 Auto 1967 Cutlass Convertible 1967 Cutlass four door daily driver 1968 442 Auto 1969 442 W30 Auto 1970 442 4spd 1971 Cutlass Flat Top Wagon 1973 Che*vy 3/4 Ton 454/TH400 Tow Vehicle Only the tow vehicle is finished!

May 20th, 2009, 05:56 PM	#5 (permalink)
ctrain22 Registered User Join Date: Oct 2008 Location: Ventura, CA Posts: 141	Is there really a difference between the G & GA or K & KA heads? These are GA and KA. __________________ 68 442 Convertible

May 24th, 2009, 05:17 PM	#8 (permalink)
ctrain22 Registered User Join Date: Oct 2008 Location: Ventura, CA Posts: 141	I am leaning towards using the KA heads, but I think I read somehwere about the exhaust crossover needs to be blocked? Can someone enlighten me on this issue. Boy, this is not like chevy where you only had to deal with round or rectangle heads. Do the GA heads have the same characteristic? If the GA heads have the big valves (which I suspect they do), would they be a better bet. This is not going to be a drag car, just good street performance driver. __________________ 68 442 Convertible Last edited by ctrain22; May 24th, 2009 at 05:32 PM..

May 26th, 2009, 07:02 PM	#11 (permalink)
64Rocket Registered User Join Date: Sep 2006 Location: Union City Calif.94587 Posts: 301	Just as has been said, for a daily driver any of the heads will do. The valve size will not make any difference. For a cruzier, troling the streets, long drives in the evening, after you close the hood no body can tell the difference. Flip the coin and pick which ever. Gene __________________

May 17th, 2009, 01:57 PM	#2 (permalink)
442Harv Registered User Join Date: Mar 2007 Posts: 119	Their both good heads. G,s are 71, so have harden seats. K,s are W30 replacement heads, and use on a lot of boats. K ,s may have the larger valves? If they need new valves you can put in larger valves.,in either.I would probaby use the K. But if you want to sell a set, you could go with the G,s as the K,s may be easier to sell, and bring a little more money.

May 20th, 2009, 06:15 PM	#6 (permalink)
chris83 Registered User Join Date: May 2008 Location: rockford Posts: 72	i would go with the g heads but if you can find a set of big valve c heads you will have more power than you can handle make sure they are the big valve and not the small valve heads you wont be disappointed

May 21st, 2009, 04:26 PM	#7 (permalink)
Warhead Registered User Join Date: Mar 2008 Location: Phx, AZ Posts: 311	Purchase a brand spankin new set of big valves, and have your machinist correctly install them in whatever set you think will look better on the car. They will flow almost exactly the same as the other, and be within 2% of the C heads (no porting). Get 2.125 intakes, 1.625 exhausts for max power. See my response on ROP concerning spring seat depths. JMGDO Jim

May 27th, 2009, 11:49 AM	#12 (permalink)
csouth Registered User Join Date: Nov 2008 Location: Detroit, MI Posts: 194	Not trying to hijack the thread, but since you guys were on BB I thought I'd ask. I know a guy selling a 455 with J heads for @ $400. I did hear that these were restrictive and should be avoided. I know its a newb quest, but are engines these even worth buying? __________________ Chris Takin' Baby steps.... '72 Cutlass S Last edited by csouth; May 27th, 2009 at 11:53 AM..

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