Big bore and valves
 

Inherited a disassembled 59 motor with 3.400 bore and matching pistons and a 4.00 in crank,- .010/.010 on full floating mains and rods. The intake seats are ground at 30 degrees and supposedly for 1.625 dia intakes. Having the block sonic tested before going any further and if it checks out can someone suggest a source for these rings, 3 per piston, and how do I measure the valve seats to verify/determine valve dia?. A source for these big valves and I would like to have the seats reground for 45 degrees. Also have a Howard M8 cam...any suggestions on specs? Thanks.

Re: Big bore and valves
 

Give me the ring widths and I will tell you the set number if one exhists without buying open stock rings.

Ronnie

Re: Big bore and valves
 

Sounds like a 3.3/8 + .020 with a little ware. Use SBC valves and the M-8 is very mild

Re: Big bore and valves
 

Grinding the seats back to 45 degrees is akin to running with one plug wire off to save gas.

You are going to have quite a bit of static compression with that cam and cubic inches. A longer duration cam ( about 270) will probably help the detonation problem at low speeds for street use.

Re: Big bore and valves
 

It was suggested to grind the seats back to 45 for longevity...but not cast in concrete.. thanks to all for your input and help. Keep the info flowing...I can't afford to make costly mistakes.

Re: Big bore and valves
 

You will loose a lot of valve face dimensions trying to grind back to 45 "from" 30.Not the same as going "from" 45 to 30.Seats will sink on you also grinding back to 45.There is no appreciable difference on a Flathead street engine to deviate from 45 deg.

Ronnie

Re: Big bore and valves
 

I have 30 degree valves in my 59AB with 100K miles. You have a bigger oppering with 30 than 45 with the same cam lift. Walt