boring out + valve question

well ive been bugging you guys for a few months and ive
got a few more questions for ya , ive examined my engine block and had it xrayed for cracks and acid dipped and it appears as though i can go as far oversize on the cylinder bore as i want but ive read that 40 thousands is a tad to much and it gets to close to the water jackets is this true , should i stay 30 or under? also im looking for a good supplier of sterilite valves and valve seats , ive already shaved the head and had it dipped so i guess its time to move on to installing valves ,( those of you that reccomend moss obviously have a bottomless wallet so please dont bother) oh by the way its a 69b

This a great time to call 'The Team' at Brit-Tek. They have an outstanding reputation, esp in the engine mod area. I had not heard about being cautious to .40 over, I had heard to be carefull if you were going .80 over+ (2 litre). In this case you have already been given the green light by your machinist so I would feel comfortable but what do you have to say Tom B? The number for Brit-Tek is 1-800-255-5883 9am-6pm (eastern).

I wouldn't boar any more than it takes to clean it up. The difference in HP between 10 over and 40 over isn't enough to talk about.You have got to remember .010 is the thickness of a sheet of paper. If you take it to 40 over that block is done for future rebuilds without sleaving it.

Can't argue with that, defer to Tom's judgement Kenny.

Yeh, Tom's right again.

Tom is right about boring it out. Just clean it up.
FYI :
The 1798cc (109.8 ci) engine bored .020 only goes to
1822 cc (111.2 ci). If you go to .040 then its1845 cc (112.6 ci). I agree with Tom completely, the 1.4 cubic inch gain from 0.020 to 0.040 over is not going to make much difference. Even if you went to 0.060 over it's only 114.0 ci. IF you go more than is necessary, you reduce your chances of another rebuild at some future date.