Where can I find 283 steel shim head gaskets for a 283 Chevy? I had them on back order with Summit for three months and they finally closed it out saying they can't get them. Thanks
I deal with a warehouse that shows as having over 40 in stock. I could arrange a drop ship if you're interested. The P.N. is FelPro 7733SH-1 and they show a compressed thickness of .015", but they do have a bore diameter of 4.100" which means that they are actually intended for a 350, so they wouldn't right at the edge of a 283's bore. I'm planning on eventually using a pair on a 283 I'm tinkering with. FWIW....they'd be about $11.00 each plus the shipping charges from Michigan. Lynn
RockAuto has Mahle brand steel ones, 4" bore, for under $10 each. Is the steel shim or bore size critical to you?
Why are you using a steel shim gasket rather than a regular over the counter head gasket? Just curious, -Abone.
Jeff, on the early 265's, 283's the compression ratio is pretty sensitive to head gasket thickness, due to the small bore. A .040" composite gasket designed for a 350 or 400 would lose 1/2 to a full point of compression.
Thanks to all. What ROOTHAWG says is why I don't want the big bore 350 types or the composite ones. I will start checking again but want the small bore ones.
I recommend SCE 511961 gaskets for the 283. Got a set currently on the 283 in my 39. Jegs says they will ship direct from SCE on 12/7. https://www.jegs.com/i/SCE-Gaskets/829/511091/10002/-1
^^^This is the best way^^^. Occasionally, you can fine steel shim head gaskets on that auction site meant for the 262, 267, 305 engines. Also, look into marine applications for them with the same engines. And yes, stay away from the "universal fit" head gaskets. I have a supply for my 265 and 283 project engines. I am Butch/56sedandelivery.
The above ones show 3.960 bore size on the package but on Jegs site their description shows bore size at 4.090. I guess I could contact the manufacture. Thanks again for the expertise!
Just checked with SCE and they say no longer available. Maybe in the spring. That's the problem everyone wants to sell you stuff for a 4 inch bore...."it will work" Yea and one size fits all! Maybe the flatheads went through this faze once until they became popular again. SBC may have to wait awhile. Not everyone wants an LS motor.
The GM steel shim gasket P/N 3830711 has a 4" bore size, I remember from my GM parts days that was in the catalogs as fitting everything from 265 to 350 engines despite the bore size difference. There was an earlier number, it escapes me at present but it started with a 37 prefix but that was long gone by the early 1970's era at least from GM.
This may have some good info. EDIT####Maybe not https://www.jalopyjournal.com/forum/threads/305-steel-head-gaskets.1137912/
I’m curious. Has anyone seen a performance loss running a 4in bore gasket on a smaller bore engine like the 283?
I did a quick calculation last night and the difference I came up with was enough to worry about. It went from 9.16:1 to 8.5:1. I always worry about it on my 265's, 283's and 301's. It's like raising the deck height by .015". You probably wouldn't feel it in the "seat f your pants" gauge, but when you are talking about 5-10 hp, when you are only making 220. It's enough to try and avoid. Just my humble opinion.
Visualize a cylinder filled with fluid. If you fill every nook and cranny with fluid, the volume increases dramatically. So you have raised the cylinder by adding .015" to the height, and then you have to think about the difference in the bore as well. The fire sealing ring is way out away from the edge of the bore. The 283 is a 3.8750" bore stock, so for giggles lets say .030 over on bore so 3.905". If you order a gasket that is 4.100" That's just short of .200". All of that extra space gets filled along with the .015" of increased height. On a 440 Dodge or a BBC it's a nothing deal, but on a wee block, it counts. Did that make any sense? In my head it did....
Oh yes, I understand completely. When I get to work tonight I’ll look at it as well. I’ve never been concerned with a small change in CR, I was wondering what was happening if say the quench was good (assuming compressed gasket is the same) and how flame travel would/could be affected by the extra area under the head/block. Not to bring OT into this, but GM used the same .022 (to my knowledge) compressed gaskets on 305’s and 350’s during the 80’s and early 90’s in the TPI engines. I’d always wondered about what if a proper sized head gasket was used for the 305, would it have helped? Just being an inquiring mind
Actually, the quench would have been right with the steel shim. Figure deck height at .025" plus the .016" gasket gets you close to the .038-.040". For production purposes GM would have said "close enough". The 305's did also have a similar gasket, but it was composite. I think it was thinner than the 350 standard gaskets as you stated. It seems like it had a cardboard feel, rather than a composite laminate. It's been a minute, though. I used to be able to buy the Fel Pro version of the 305 gasket, but I am guessing that went away a long time ago. Glenn (@AHotRod )would know. He used to be a rep for them, many moons ago. I did find this one. The bore is smaller, but the compressed thickness is still too thick. https://www.summitracing.com/parts/fel-8510pt/make/chevrolet
I asked when I was doing the OT 350 on another board about the head gaskets. Now I did not research it much, but the closest I could find for “factory replacement” was. Mahle. Comp with a steel shim at .022 compressed. Stated on the infor was 305/350 for my year I needed. Now these were masses produce vehicles, so probably fit the “one size” thing Regardless, just to be clear, I’m not discounting a thing/ word you have said. . It was just a brain tickler for me
Way too much emphasis in nothing...do the math. Difference in compression ratio on a 283 between two .015" gaskets, one with a 3.960" bore and one with a 4.100" bore....is 0.03:1 difference in compression ratio. 3.905" bore, 3" stroke, 58cc head, 4cc valve relief(Flat top piston), a .025" piston-to-deck, and .015" x 3.960" bore gasket = 9.42:1 compression. 3.905" bore, 3" stroke, 58cc head, 4cc valve relief, a .025" piston-to-deck, and .015" x 4.100" gasket = 9.39:1 compression. Just use the 4.100" bore version, it won't make enough difference to notice. You'll have a bigger difference in compression ratio if your block isn't decked square than you will worrying about a little bit excess gasket bore diameter. Gasket thickness, on the other hand, I will agree is critical, because of the area of opening involved the volume is a lot bigger gain/loss.
Eric, I think the compressed gasket makes a bigger difference, rather than the larger bore size. I'm not sure that the steel shim is even available in the larger bore.... I've gotten lost since we started. I'll have to read the whole post again.