Hardened exhaust seats are needed in situations where the engine will be under a 60-70 percent load for long periods, like in a heavy car climbing grades (or just dogging it) or truck actually working. I've only seen one instance where exhaust seat recession actually occurred, and it was in the latter. What about it guys? Let's here your experiences. And about the Impala, was it a 327 2bbl?
Great thread! I'm building a .030 over 283 for a Deuce roadster. I have a Edelbrock C357 three deuce Rochester 2GC setup and am planning on running a mild 327/350 cam. I want decent performance but am really shooting for good gas mileage for when gas gets ridiculous again. I would like to see over 20 mpg. Any suggestions for compression using regular gas? I have flat tops with 4 valve reliefs for now. And is the cam the right one for what I want or ?? I'll have to check my head stash but I think I have a set of pwer packs and a set of double humps. Do I need the hardened seats too. I've been told both ways. Any suggestions are welcome!
you know i really can't remeber what it was. just thought it was odd haveing the humpers and a 2 brl. but i should have bought that puppy
I'd suggest hardened seats today regardless how much you drive it. Most of these heads were talking about have been around awhile (multi rebuilds) and so even after a common rebuild in your possesion once the valves are sunk in to deep from not having that leaded cushion you'll have to move up to the next size 2.02 or maybe shaved 2.00's may work. All 283's (small bore) dont like anything bigger than a 1.94 unless you turn it into a 301. Most camel humps already have 1.94's so the next step is a 2.02. valve. For cams your 327/350 cam is a good choice good gas mileage and also a bit better the 275h dual energy from Comp Cams Ive used both of these cams in my cars. I know theres newer stuff out there but these are still a good choice today. For compression keep the flat tops power packs or camel humps will keep it anywhere between 9 to 1 & 10 to 1 depending on other factors.
I run a standard bore 283 with stock pistons, a 350 hp 327 cam and dual WCFB's on the street. Up till last year I ran the 283 heads but I switched to the 461s last Aug. She runs fine on regular gas and I'm getting about 15 mpg on the highway in my 57 Corvette. Bob
good thread, now I have a question also. I am going to be running a 283 std bore in my 1930 model a highboy the heads have had hardened seats installed. the casting number on the heads is 3884520 not sure the valve size. I have an Eld. 3 duece intake I was wanting to run. the car is an auto. see any problems with this combination? Thanks
tracer55 , your heads are what we have been calling 520 heads..they came stock with 1.72 intake valves and 1.5 exhaust valves. but they may have been changed to a bigger size , so the only way to know for sure is to measure them. i see no problem with the parts you will be using...depending on what camshaft the hardened seats is a good idea. i agree with Herez , put them in. checking the invoice from the machine shop where i just had them put in a pair of 520 heads i see it cost me $98.92 to have done
I'd listen very carefully to what Duntov said ... and take notes, if you're interested in serious performance enhancements. He had my undivided attention when he said he got the heads from Ed Mabry. If you check Mabry's record you'll find he's built some incredibly fast cars and bikes.
I have these heads at the machine shop right now. I'm having a mild port job done and then I'm gonna run them on my 283. From what I understand they perform great on a 283...
I have a friend who has a machine shop in Georgetown TX. He builds Chevy 383's with Edelbrock aluminum heads that run the 1.94 valves that he ports himself. The motors make 450 hp with 1.94 heads.
What is this 350/327 cam I keep hearing about? I want to change the cam in my 283 when I bolt my 305 heads on. Is this a good choice? Who makes it?
I have a friend that was a race engine builder in the 50's,60's and the 70's. He would always use the Power-Pak cylinder heads on whatever he built. Hell he even went as far as to install Angle-Plugs into a set of Power-Paks. Just makes you wonder why !! He had a good reason I can promise you that >>>>.
Chevy made it...the actual part number is 3863151. it is a single pattern cam with .447 total lift and 222 degrees duration at .050 lift. however , just about anyone who grinds new cams makes a copy of it.
I can make the intake work with the Vortec heads. They do make the 305 head in dual patter also. I like the heads from the 305 HO for a 283, if I got to go late model. They'll flow fine for the RPM range hes set up to run. Ohterwise there the 283 Power pak heads are still around. they work well with very little work and you can tell everyone its old school.
I've read that the aftermarket has made some improvements over the stock Chevy 151 cam. Is this true or is the original Chevy cam best for a mildy built 283?
Modern cam grinds are light years ahead of the old L-79 "151" cam but it still works good, it's cheap, it sounds sweet in a 283 and it's as traditional as it gets in a mid to late 60's build. You can get the same lopey idle and much better performance from one of the newer grinds but back when I was a tadpole it was cool having a "327/350HP" cam in a 283.
This thread couldn't come at a better time for me. I spoke with a machine shop about my 283 last week. Going to get everything checked out and cleaned up and ready for a rebuild.
Any input on the 1955 523 heads? I am thinking of running a set of them on a 283. Uncle ran them on a 265(bored 0.125 to 283) when he was a kid.The '56 210 was a screamer.
Great thread, I am going through the same dilemma right now. Just finished tearing down a '58 283 to go in my '40 Pickup, trying to make it old school so I want to run the offset valve covers. Sounds like I need a set of early power pack heads.
Hotrod40coupe, if the 283 you have is a 1958 model it already has stagger-hole heads since chevy did not change to straight hole till 1959. My recomendation on all those pre 1970 heads is to change to later 1971 and later valves rather than replacing the seats.The valves that have the dish in the center of the valve are softer. The later valves are flat across the head of the valve. Also I did not think the 520 heads with the diamomnd came out till 62. I also never heard of a set of cast iron heads being converted to angle plugs. We used to "Angle Mill" them.
I have a question for you guys i am in the process of getting me 32 chevy 5 window coupe rolling i have a .040 over 283 which makes it 289 it has flat top with 4 valve reliefs in them and it looks as if the engine has been decked.I want to run the Egge 283 hi performance domed pistons that they are reproducing and i have a set of 520 heads and the engine has an original steel crank i know the engine comes back as a 61-64 block but my question is am i gonna have any problems with the pistons and head clearance.I am also running a tunnel ram on this engine and want the domed factory style pistons to bring up my compression.I am also trying to figure out what the best cam would be to run with this setup also.I would like to run an Isky Solid cam with the set of crane roller rockers i have.Will all this work together?
Slickster , i don't think you should have any problems with those pistons as they have valve reliefs in them. i would do a quick check with some clay. i believe that the set of 8 will have left and right banks , so don't mix them up. with powerpack heads you are probably just over 9:1 , not sure what these pistons will get you. here is a picture from Egge's website:
my motor is 40 over and with flat tops and 520's -62 chamber it would be around 8.5 -9.1 comp. You probably have a zero decked block nothin to worry about it just raises your compression on those flat tops a small amount. My motor has the old replacement fuelie TRW's. 11.00:1. and block hasnt been decked. Egge picture above same style. There is also a non stock replacement piston that was I think 12.5:1 that was used as a fuelie piston too. I think Egge catalog hs this piston available. The old "fuelie" replacement pistons Ive seen Egge carries would raise your compression to 11.00:1 with a stock deck height and camel hump 461s or 62's 62- 64 -chamber heads. Being that you have a decked surface it would probably raise the compression a bit more 11.5 or more. With a 1965 -67 30/30 solid I had a bunch of piston/valve clearence but (ALWAYS CHECK!)
I have the 60cc chamber heads they've been shaved just a bit to make them flat but it made me wonder just cause i don't wanna bend valves.I also wanted to raise the comp ratio to work better with the tunnel ram and make it a little more stout sounding with open headers.Any suggestions on what size cam to run as far as a solid isky goes?
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