well i searched this and found the valves on a gen 1 small block 350 to be 1.94/1.50. however i measured mine on mine came out to be something like 1.75/1.50.

it didnt sound right so i checked and rechecked and i kept getting 1.75 for the intake...is this some kinda special crap motor? i never heard this.

 

there were 3 or 4 different sizes, it depends on what heads you have. what's the numbers on them?

 

grrr...k lemme go get dirty...

 

the number will be under the valve covers, check both heads and make sure they match

 

k dont know how relavent this one is...GM 47, then i think the casting number is 3888881.

 

881 heads have big valves. check your numbers again because some of those 8's are probably 3's

 

lol. ok. but im looking at the right part right? the casting number is the 7 digit one. or is it the C--- one?

 

ok. 3988891. that sound better?

 

Not finding that number on www.mortec.com , or anything close for that matter. Although there were a few motors that came with 1.72 valves, I am guessing this is the number you are getting.

 

3998991....72-73...307/350......75cc chambers

that looks close enough. so if i have 1.72 intake valves where can i get replacements? must be rare cuz summit doesnt have them.

and how hard is it to swap to 1.94 valves? is it as simple as grinding the seat or would i need new ones?

 

3998991 307/350 68-79 1.72/1.50 76cc

 

You can get them at a local machine shop.

Don't waste your cash installing 1.94s, the tiny ports and bowls would kill any advantage the larger valves might give you. I wouldn't bother with those heads, you can get inspected/rebuilt heads from aerohead for 399:

http://www.aeroheadracing.com/id7.html

 

wow thats a great deal. i'll have to look into that. im pretty much building this motor for fun, so id actually rather get some heads with 1.94s already so i can rebuild those.

thats for the help guys, i can always count on this board to have the answer.

 

you can get a pair of brand new 2.02 heads from Summit for around 700$ complete with valves and springs
http://store.summitracing.com/partde...5&autoview=sku
I just put a set on my motor they look pretty good. I havent fired up the motor yet to know how they work, but for what your looking for I think its the best deal. add up what a machine shop will charge you to machine and install the valves plus the cost of new springs, guides and valves. dont think you can beat it


Wade

 

sure ya can. im gonna be doing all that myself. theres no way im going to spend that much on this motor. its just for fun. i dont have anything to put it in.