98darkhorse.com
New Member
Has anyone run these heads on a 4.6 2v? I have seen review with other engines and these heads, but not anything on the 4.6 https://promaxxperformance.com/product/shocker-sbf-modular-cnc-4-65-4-2-valve/
ProMaxx 4.6 2v Heads
- Thread starter 98darkhorse.com
- Start date
The positives i see are brand new castings, bronze valve guides, and the promise of excellent machine work.
Id be curious to know if that casting is as good or better than Ford. The bronze guide is the way to go if you want to run the engine on the edge.
A stock head can run a 1.840" intake valve on the original seat. Again im curious if the bigger valve gets a bigger seat, because the original seat material gets a bit skimpy for the big valve.
Surely the sparkplug holes are revised 9thread! I didnt see that info, could have missed it, but it be dumb not to be 9threads.
Looks like they are honest with flowbench numbers. 219cfm at .500lift for the cnc ported version and big valves is very conservative especially for $1050 per head for the bigger valve version. I remember inflated flowbench numbers wayback when 2v modulars were hot and companies competed for your dollars. Promises of great potential with their product only to discover minimal hp gains over stock. The money spent didnt justify the hp gain. Honestly alot of that still holds truth today with these modulars. Especially with them FB hero's.
If you had a newer set(05-11) of stock pi heads that are in excellent shape, took them to a machine shop, had them prepared like the heads from promax, you would be out roughly the same amount of money.
Keep in mind that pi head ports are known to stall after .500 lift and if you take note of there own flowbench numbers you notice only a 15cfm improvement for more lift and a bigger valve.
I can see the stock version being worth the money. Not so much for the bigger valve vesrion
Id be curious to know if that casting is as good or better than Ford. The bronze guide is the way to go if you want to run the engine on the edge.
A stock head can run a 1.840" intake valve on the original seat. Again im curious if the bigger valve gets a bigger seat, because the original seat material gets a bit skimpy for the big valve.
Surely the sparkplug holes are revised 9thread! I didnt see that info, could have missed it, but it be dumb not to be 9threads.
Looks like they are honest with flowbench numbers. 219cfm at .500lift for the cnc ported version and big valves is very conservative especially for $1050 per head for the bigger valve version. I remember inflated flowbench numbers wayback when 2v modulars were hot and companies competed for your dollars. Promises of great potential with their product only to discover minimal hp gains over stock. The money spent didnt justify the hp gain. Honestly alot of that still holds truth today with these modulars. Especially with them FB hero's.
If you had a newer set(05-11) of stock pi heads that are in excellent shape, took them to a machine shop, had them prepared like the heads from promax, you would be out roughly the same amount of money.
Keep in mind that pi head ports are known to stall after .500 lift and if you take note of there own flowbench numbers you notice only a 15cfm improvement for more lift and a bigger valve.
I can see the stock version being worth the money. Not so much for the bigger valve vesrion
OP
OP
98darkhorse.com
New Member
Found these on the market place, here are the pictures from it, these are best pictures I can find of them. I want the TFS heads, but they are pricey, plus other components to make it all come together, got me wanting to swap to a 427 small block in this and really get down.
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That’s a really nice set of heads. I like how they did the cam cover bolt holes. It’s set up to use Windsor and Romeo covers.
The castings do look good. And if i were a performance head company wanting to cnc port the heads, I would be darn sure the port walls were beefy to ensure no break through when performing the work and the extra material for multiple type valve cover bolt patterns. Id say they didnt cut corners with designing these heads. If you can score a new unused set secondhand at a great price, grab them.
