Sounds like it has to be done to clear the valves. I’ve owned many Pontiac v8’s that had it done from the factory. Sent from my iPhone using H.A.M.B.
Your better off with a set of 305 4-bbl heads.... 57-58 cc combustion chambers instead of 64-65cc from the 461 castings...
I have deleted my entire,previous response in order to answer the OP's specific question; "what do ya'll think about bore notching a 283 engine?" This is JMO, but I think it's putting a bandaid on in an attempt to "fix" an avoidable problem that began with poor planning. Nothing about this 283 is known (overbore, piston type, etc.), only that he wants/needs to notch his block. Is your machinist willing to do this for you, or do you plan on attempting it yourself, and if so, how do you plan on doing it? Overall, I think it's foolish; JMO. I am Butxch/56sedandelivery.
Well already know all these heads with a 62cc /and 2.02 valves,do all this to lower CR has dome piston to take care of this problem,this is why iam asking about bore notching . not CR ?
It's been said that "some" not all 283's can be punched to 4.000". Have the block sonic tested and you'll have your answer if it'll be safe.
R - ONLY if you need to. Don't...go as far as the location of the top, of the top piston ring. Stay about .030" above the top of the top piston ring. I need to notch the bores on an engine I'm building. Despite the expert comments above...I also...am going to a larger valve than stock...PLUS...in my head reworking, I moved the intake valve away from the exhaust valve, hence my need for notching of the bores in my block. Yes, the pistons are well capable of making up for the loss in compression from the notching..! Mike
I have to ask, "Why are you building a 283"? If you are trying to build a car that has an original 283, I can understand that you want to try to stay close to original. Beyond that, it will cost just as much if not more to rebuild a 283 as it would a 350. A high performance 283 that is streetable will provide lackluster performance compared to many of todays economy cars. No fun gettin dusted by a Prius ! A good 283 block is probably worth more money to a restorer than its worth as a performance starting point. With todays combustion chamber design technology I have to wonder how notching affects the combustion chambers ability to compress and burn fuel properly. Build an engine that will provide good low end torque rather than something that has max HP and you will be far happier on the street. Putting larger valves in a head does not always result in a performance improvement and can actually hurt performance. 283s were legendary in their day, and one of my fondest memories was watching two 55 Chevy gassers go head to head with their open exhausts. One had fuel injection and the other had 2 fours. I was an impressionable 14 year old. It was a fantastic side by side race all the way. Looking back, I think it was the noise of the open hedders that made it seem so surreal in my mind. Today there are plenty of street driven cars with mufflers and cats that would easily outrun them. (Note: Yes I know 55s weren't 283s but they were gassers with smallblocks in them and 327/350 versions were not available then....but they were probably bored and maybe stroked.) Decided to add something else. Respectfully, I do not understand the logic of what you are trying to do. The costs and knowledge to build an engine like you are describing seem to be counter productive. If you modify the block and use the larger valves, you will probably need a special piston to make it all work properly. Just notching the block and using a stock piston will lower your compression ratio. It appears that you will need to expend a lot of money to make it work, and then have limited power when done. Not meaning to be critical here, just trying to help you attain the best bang for your bucks. Please explain a little more on what you are building, and what you hope to have when done. Best of luck, Mike
With the Canted Valves in the 396 and the notched block it still flows decent. If you notched a 283 to take the 2.02 valves wouldn't the block shroud the valve? I just picture Air flowing in and hitting a proverbial "air dam" into the cylinder.
Seems like more ass ache than it’s worth. The little 283 cylinder can’t use the all the flow of that big ass valve anyways,,,slow the velocity down enough and you’ll kill it not make it better.
I can see building a 283 for a hot rod if you have one handy, and you are going to put it in a light weight car like a T bucket or roadster. A free revving small displacement engine is a lot of fun in a light car. I wouldn't spend a lot of money on it. Do a basic rebuild with cam, headers, intake and 4 barrel. Doing enough head work to require bore notching seems like overkill. Unless you happen to have the big valve heads on hand. Then go ahead.
Probably so,,, Let’s say a fella has to be at near 283 ci for some competition or class limits Or Let’s say a fella has a bunch of stuff just laying around and wants to put it together for the cost of gaskets and a case of beer.
So you can't trade the 2.02 heads for 194's ? The head gasket on the 396 was designed for the notch. You also have to notch the gasket as it will interfere with the air flow around the valve. When we were running dirt modifieds we experimented with a 366 Small block that had notched cylinders and head gaskets that were done at the machine shop. The engine actually had too much torque and would break loose the tires on the straightaways. Went to a 377 and that was the ticket. I saw the results of a 400 block (383) where it had been notched by the owner.......blew an 1/8 deep groove between the cylinders. To take advantage of a 283 with 2.02 valves you will need to turn around 8500 rpm's
uh....I think the idea of the notch, is to get the bore out to 4" near the intake valve. Not to go past 4-1/8", like that guy did! And using normal 4" bore gaskets would eliminate the need for notching the gasket.
It's great to hear everyone's feedback and gives the OP somethings to think about. Tell us what your plans for use and vehicle specs , so everyone is on the same page. If you can afford a rebuild then you can't be that destitute to find a 350 block kicking around that would put you ahead of the game .
Thanks for a the comments .what i have is a 283 bored 3.915 s10 pickup i got on a trade with block in truck already,had the 461 castings already did not want to buy more heads tuck has 6speed tremec already didnot want to have to buy anything thats why asking about bore notching
Get yourself some 305 HO heads or same era 305 truck van heads and steel gaskets and you’ll be happy . They are cheap maybe trade off the big valve heads ? Put the big valve heads in n that 283 and you won’t be happy with the engine
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