882 heads with domed pistons? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

57Suburb · 06-06-2017, 02:47 PM

I've got a 350 short block that I pulled out of a Camaro a few years ago that I'm thinking about doing a quick refresh on to stick in one of my 72s. I pulled it because it had domed pistons in it and I could never get it to run right on anything less than 93 octane gas. It had power pack heads on it at the time which was giving it 12:1+ compression. Would a set of 882 heads (I have a pair) lower the compression enough to run regular pump gas?

68gmsee · 06-06-2017, 05:08 PM

Quote:

Originally Posted by 57Suburb

...Would a set of 882 heads (I have a pair) lower the compression enough to run regular pump gas?

A lot of people don't like those heads, but I've had a couple of 350's with the 882 heads and never had any problem with them and no problem using 87 octane with them. Most of my driving is regular driving and not racing.

68gmsee · 06-06-2017, 05:11 PM

Just reread and noticed that you are leaving the dome pistons in. I don't know if the compression would be low enough for regular gas though.

Marv D · 06-06-2017, 07:20 PM

Not knowing how much dome it's impossible to do anything but guess. A piston # with a dome volume,, knowing if the block had been decked,, you can get a lot closer.

But WAGGING it here,,,, If it had a 12cc dome and 64cc chambers of the old Camelhump heads (iif it was exactly 12:1 with the old combintion of parts),,,
Swaping to a 76cc chamber of the 882's would yield 10.3:1 static compression.

I would not be shy with the cam duration and pick one wiht little or NO advance ground in to it and it should be pump gas tolerable.

57Suburb · 07-11-2017, 02:28 PM

So, I'm picking up a set of 441 heads (better casting) that have been milled to accept 2.02/1.60 valves. Also did some research on the pistons I have and they are the TRW LT1 knockoffs with a .100 dome. Plugging in some numbers, it looks like the static CR will be in the 9.75:1 range. I'm going to be running a FiTech with this motor, so I'm satisfied with the CR. My question now with this budget build is about the cam. I have a Comp Cams 262h new in the box that I"m thinking about using with the combo.
Lift .462"/.469" Duration 262°/270° Duration @ 0.050":218°/224° Lobe Sep. 110°
RPM Range 2000-5300
Not enough, just right or too much?

Tom · 07-11-2017, 06:52 PM

Edit: just noticed your last reply, oops lol. That cam will do just fine.

06-06-2017, 02:47 PM	#1
57Suburb Registered User Join Date: Apr 2014 Location: Southern Iowa Posts: 306	882 heads with domed pistons? I've got a 350 short block that I pulled out of a Camaro a few years ago that I'm thinking about doing a quick refresh on to stick in one of my 72s. I pulled it because it had domed pistons in it and I could never get it to run right on anything less than 93 octane gas. It had power pack heads on it at the time which was giving it 12:1+ compression. Would a set of 882 heads (I have a pair) lower the compression enough to run regular pump gas? __________________ 1972 C30 Grain Hauler, 350/400 1967 1500 GMC Stepside SWB, In Transformation Process 1967 RS/SS Camaro 350/TKO600

06-06-2017, 05:11 PM	#3
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: 882 heads with domed pistons? Just reread and noticed that you are leaving the dome pistons in. I don't know if the compression would be low enough for regular gas though. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...

06-06-2017, 07:20 PM	#4
Marv D Registered Truck Offender Join Date: May 2008 Location: hells training ground (aka Ariz) Posts: 3,118	Re: 882 heads with domed pistons? Not knowing how much dome it's impossible to do anything but guess. A piston # with a dome volume,, knowing if the block had been decked,, you can get a lot closer. But WAGGING it here,,,, If it had a 12cc dome and 64cc chambers of the old Camelhump heads (iif it was exactly 12:1 with the old combintion of parts),,, Swaping to a 76cc chamber of the 882's would yield 10.3:1 static compression. I would not be shy with the cam duration and pick one wiht little or NO advance ground in to it and it should be pump gas tolerable. __________________ Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral.

07-11-2017, 02:28 PM	#5
57Suburb Registered User Join Date: Apr 2014 Location: Southern Iowa Posts: 306	Re: 882 heads with domed pistons? So, I'm picking up a set of 441 heads (better casting) that have been milled to accept 2.02/1.60 valves. Also did some research on the pistons I have and they are the TRW LT1 knockoffs with a .100 dome. Plugging in some numbers, it looks like the static CR will be in the 9.75:1 range. I'm going to be running a FiTech with this motor, so I'm satisfied with the CR. My question now with this budget build is about the cam. I have a Comp Cams 262h new in the box that I"m thinking about using with the combo. Lift .462"/.469" Duration 262°/270° Duration @ 0.050":218°/224° Lobe Sep. 110° RPM Range 2000-5300 Not enough, just right or too much? __________________ 1972 C30 Grain Hauler, 350/400 1967 1500 GMC Stepside SWB, In Transformation Process 1967 RS/SS Camaro 350/TKO600

07-11-2017, 06:52 PM	#6
Tom driving is in my blood Join Date: Dec 1999 Location: Mesa AZ Posts: 5,692	Re: 882 heads with domed pistons? Edit: just noticed your last reply, oops lol. That cam will do just fine. __________________ -78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me.



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