When taking my engine out I notice 2 adjacent plugs had very small gaps as if they had been hit, that was 3 years ago, now when I had the heads cleaned up and inspected, the machinist told me I had 2 slightly bent exhaust valves.. also adjacent, in both cases I dont know which ones, the gaskets i will use are felpros and they are .020 thicker than the steel gaskets that were on there.
My engine is a 283  from 1959 or 1960, the heads are from 58-61, part #3748770 and they say X-58 on 1 side, I believe these to be 58 power pack heads 64cc. The pistons in the engine say .040 on them and they are pop ups  and the spark plugs were AC R44s...do I have the right plugs in the engine,if I do could i space them up a little, I also noticed small gouges on the outer portion of each of the piston tops as if something had been hitting at one time. Any guess what the compression ratio might be...and believe it or not, the engine ran good.
My plan is to clean it all up, timing chain, rear main seal, all new gaskets, paint and do up the whole engine bay,...put the motor back in for a few years and then do the whole drivetrain over to a streetrod  

I have seen the pits in pistons before.My thoughts are it may have ben detonation or coolent leaking into the combustion chamber.I dont understand the spark plugs gap question.Do you mean the porcelin was cracked? I am thinking this engine has a verry high compression ratio.This will require a verry high octane fuel.What was done about the valves? You may have some damage done to the piston lands.Or the part between the top compression ring and the top of the piston.I think at least you have some valuable heads.If not a rare engine all tgeather. I understand the point of why rebuild the whole engine if it runs good.I have many engines sitting behind my barn that ran god and wuld still be running good.But I dissembled em and did not like what I saw.They were all free at least.

or

I just wrote you a novel and when i went to post it, it said could not be displayed and it got rid of all the text, i am pissed, i will try to give you the short version... not pits, they are gouges from side electrode hitting, plugs are wrong, R44s indicates extended tip and should not have been used with pop up pistons.

Porcelines were not cracked at all, just the gaps closed from piston hit,  i am assuming.

My compression read 185, but i only tested one cylinder because the piston hit the brass adapter, thats when i decided to pull the heads. I do have a nice gouge where it hit, i was planning on wire brushing the piston tops anyway, so i will try to clean up the gouge with some scothbrite. How much damage can i get away with?

Sorry to hear abut your novel.I only type like 15wpm.Um ,I dont know .What I was getting at was the compression rato with the tight chambers in the heads and the pop up pistons you may have a compression ratio of like a serious racing engine.Anyway I see the spark plug problem. If you really push yhe combustion temperature up the pistons may burn through.Gan you make a guess on how deep the gouges are? Like .005? Or more.I know If you take the pistons out you will decide on having it bored and next thing you know u have 5oodollars in a kit and so on.Trust me I am not gooing to push you into rebuilding it .It did run good.Um the plugs you should use will not have anything after the number R43 or R44.I have had the gaps close up fron detonation with the right plugs installed before.Also had small holes {black specks}  burned in the porcelin on the firring tip.This was my fault with a lean condition or too much timming.If you ever hear detonation and then it does noy idle well or misfires you need new plugs.With headers you can use a spray bottle with the engine running and the primary tube that takes the longest to burn the watter off is not firring well.I am still curious about the bent valves?Did too mush heat cause this?Also do you have hardened valve seats installed? I really dont want you to make your piston decision on what I say.What damage could happen If one burns through.The gouges could become a hot spon and create detonation.They may be factory forged pistons and the dome is thicker to the bottom I think.  

The.040 over is a concern for me.I recently took a 283 block that had been punched out to 4.00 and made myself a little screamer out of it.I used keith black aluminum pistons(among other little tricks)I got almost everyone on here on my ass telling me it wouldn't hold together.I'm very interested in the outcome of this.Keep us updated.  

Why would .040 concern you , I think I could go 3 times that safely, if i am not mistaken.  

A 283 stretched by +.040" isn't a concern.  That will net you a bore of 3.915".  Not a problem. 

The problem is when you stretch a 283 to 4.00" with a +0.125" cut.  The 283 core isn't the same as the 302/327/350, and 4.00" is pushing a 283.  Even with that said, many rodders have punched a 283 to 4.00" (netting a 301cid).  In fact, that was the hot ticket prior to the introduction of the 327.    

The block sleve is not much thicker then it has to be.I have read that you should not bore more then .030 without having the block sonic tested.I dont know for sure what this means.I would guess it is a way that you can tell how thick the bore is from the piston side to the watter jacket.I saw on the counter at a parts store once a real mangled piston.The guy said he tried to have his 327 taken out .060.I dont think the sleeve part of the blocks have a great deal of consistancy from block to block.  

"I dont think the sleeve part of the blocks have a great deal of consistancy from block to block."

You're right.  That's why - if a block is intended for severe performance application - it's not a good idea to bore a sbc more than .030 (maybe .040 at the most), even less on a 400.

Sonic testing does just what you thought... it measures the thickness of the cylinder walls.

I agree with the inconsistancy of the blocks.Although I have had good luck with my 283(punched to 4.00).A sonic test would be well worth the $.I have created my share of boat anchors,and some would have been salvaged if i had a sonic test done.  

I thought Ford Engines Made The Best Boat ANCHORES???????  

I wouldn't know.I've never owned a ford.  

Well have you ever owned a big boat? I have had a few fords .I dont undrrstand why they have quadropel the emission equiptment of chevy.If they are that much of a emissiom producer why not redesign the engine to produce less?The relaysa and fuel pumps(3 on a truck or van is ridiclous} is just stupid.  

That's a stubborn bunch over there.Look how long they have been making cars and to my knowledge have never had a decent auto tranny.The little pony boys around here have started cutting 350 turbos bell housings off and adapting them for their pony rides.  

i have a 283 truck engine that is bored .050 over. is that at all a concern. i dont think it has had any other modifications.