Adding 2.02 intake to J heads

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The 422 I built some years ago runs 596s I gave a Stage II porting to. they run a 2.05/1.65 valve package. They were never flowed but I guessed around 240-250 @ .500. The engine makes close to 470hp based on MPH and weight. The cam it uses is an older Crane hydraulic, with .490/.500 at the valve and around 240° @ .050. The key is low lift flow, and that's where the larger valves will help with very little other work done. I agree the gain by just addding 2.02s and a 3 angle stone valve job is minimal - I'll bet noone posting here could feel the difference in a driving car myself included - but when it's coupled with a high quality 5 angle valve job that provides a very good approach to the seat (never mind the blending or laying back the short turn) it will make a measurable difference. If you're not going to optimize the work and quality, the results will never be optimal.

I'll add - the 596 heads as cast are not enough to feed a hungry 4" stroke engine. It's not displacement - but stroke. You increase the stroke by 18%, so you need 18% more air with no other changes to maintain the same type of power curve. Without providing more air in the volume you need, you will end up with a very torquey engine with no lungs to rev. Big torque, but a steep drop in power after the torque peak. For some that's not a problem, for others it is. I'd expect it to make decent torque right off idle, and have a horsepower peak around 5-5200 depending on the cam, and after that, it will fall off fast.
 
Hummm, I'm not sure what to say about your thought train. Considering the size engine and rated stall of the converter, which will change a little since the more torque you put into it the higher it stalls. Hence the cheap route of the use of the /6 converter behind a 440 big block trick.
A little porting on a 360 head IMO is not snuff even for what your telling me. *I think* it'll run out of head at or below 4000. Perhaps, speaking with one of our resident engine builders would yield better results. This is a route I have not taken. This is a route I would not travel.

I myself would look into a 360 to build on the side and do that engine for what you want.

OH! And what Moper said.
 
rumblefish360 said:
Hummm, I'm not sure what to say about your thought train. Considering the size engine and rated stall of the converter, which will change a little since the more torque you put into it the higher it stalls. Hence the cheap route of the use of the /6 converter behind a 440 big block trick.
A little porting on a 360 head IMO is not snuff even for what your telling me. *I think* it'll run out of head at or below 4000. Perhaps, speaking with one of our resident engine builders would yield better results. This is a route I have not taken. This is a route I would not travel.

I myself would look into a 360 to build on the side and do that engine for what you want.

OH! And what Moper said.
Click to expand...


I understand what you're saying. I haven't talked to my engine builder about the heads yet (but I will). I already have a '72 318 block bored with new pistons, rods, crank and cam. But it's a 318 build. I bought it super cheap from a guy who had no use for it. I plan to strip it, sell all the new parts, take the block to the machine shop and find some good pistons that will work with the block and the heads/valves. I guess if the ported heads won't support the engine after it's built I'll just have to break down and get some fancy ones. I'm not building a race car, it will be a daily driver like it is now. If the heads will flow at least up to 5200 RPM I'd probably be happy. I just can't justify buying a fancy set of heads that flow like crazy if I'm not planning on using the higher RPM ranges?? Seems like a waste of money. Like I said earlier...with my present 3.73 gears/tires and the 2004R at 5500 RPM my car would be doing 189 MPH so I have no need for high RPMs.
Thanks for all the help...
Treblig
 
moper said:
The 422 I built some years ago runs 596s I gave a Stage II porting to. they run a 2.05/1.65 valve package. They were never flowed but I guessed around 240-250 @ .500. The engine makes close to 470hp based on MPH and weight. The cam it uses is an older Crane hydraulic, with .490/.500 at the valve and around 240° @ .050. The key is low lift flow, and that's where the larger valves will help with very little other work done. I agree the gain by just addding 2.02s and a 3 angle stone valve job is minimal - I'll bet noone posting here could feel the difference in a driving car myself included - but when it's coupled with a high quality 5 angle valve job that provides a very good approach to the seat (never mind the blending or laying back the short turn) it will make a measurable difference. If you're not going to optimize the work and quality, the results will never be optimal.

I'll add - the 596 heads as cast are not enough to feed a hungry 4" stroke engine. It's not displacement - but stroke. You increase the stroke by 18%, so you need 18% more air with no other changes to maintain the same type of power curve. Without providing more air in the volume you need, you will end up with a very torquey engine with no lungs to rev. Big torque, but a steep drop in power after the torque peak. For some that's not a problem, for others it is. I'd expect it to make decent torque right off idle, and have a horsepower peak around 5-5200 depending on the cam, and after that, it will fall off fast.
Click to expand...

My guy works to get low & mid lift flow, on street/strip engines.The peak lift /airflow numbers are saved for, nastier rides.
 
Ya mon! I'm used to building a bit hairier of a mill.
Off hand, the screen name escapes me but I can see his white Duster at the bottom of his posts where MRL built him a 470HP, 340 engine. The cam timing was really streetable.
 
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