JeepsAndGuns
Whats everyones take on bigger valves? I am thinking about it for my 4.0 stroker. I bought a complete engine to build so I can still drive my jeep. I am gonna end up doing some port work (either myself or someone else) and was wondering if it would be worth the money to go to bigger valves? I found a place that has them for about $16 each, so theres close to $200 after shipping.I havent shoped around yet so I dont know if thats a good deal or not. About what should I expect to pay to have the seats in the heads cut? Just wondering so I will know when I start looking for a shop. Oh yea, stock is 1.91 in, 1.50 ex, the new ones would be 2.02 in, and 1.60 ex.
opinions?
ironman_gq
bigger valves will help flow better if you need them if you dont the intake charge will lose velocity at low rpm and you will end up with fuel drop out that will make low speed wheeling difficult. with the stroker it would probably work pretty well with some port work (simple cleanup).
The valves are the same as the ones used in the AMC 304 so you could use the larger valves from the 360 and probably save a lot of money. most auto parts stores have them.
NAPA P/N
intake - 2112150 $10.50
exhaust - 2112147 $14.69
Holeshot
You need to know from someone who has experience with your specific engine. Too large a valve could hit the block, or if not making contact, the block could interrupt the plume or cone of gasses that form around the valve head, ruining flow. There are also hi-po stainless valves that are undercut below the guide for more flow.
On a fully ported & prepped 360/390/401, you can gain 30~60 HP with undercut 2.08/1.74 valves. I have heard of ppl using even larger valves but I do believe that takes major mods.
