LT4 Miniram and a lt4 hot cam.

[devilfish]

Ok so If I do port my heads. ANd save the money on the headers.
Do I need to go with larger valves or is stock enoug?
What gains can I se with ported 113 heads, miniram, lt4 hotcam kit?

Regards

 

[-=Jeff=-]

Ok so If I do port my heads. ANd save the money on the headers.
Do I need to go with larger valves or is stock enoug?
What gains can I se with ported 113 heads, miniram, lt4 hotcam kit?

Regards

Go to the 2.00"/ 1.56" valves.. have the 113s CNC Ported..

I am running 12.74@110 with:
Long tube Headers
Miniram
52mm TB
ZZ9
CNC L98 heads
1991 ECM

I don't have any recent Dyno #s with the 1991 ECM

 

[89ZZ4]

Jeff got my heads from a machinist at an engine performance shop in the Detroit area. He has all the equipment at home and does this as a side job. He bought a number of bare castings from a recent production run through his sources so he can build a head up using the factory prints which he has. Makes it easier to do bowl work and porting before doing the 3 angle grind seat grind. I getting some decent stainless valves (2.02 Intake/1.56 Exhaust) and he will do a 30 degree backcut on them for me. Springs will handle about .580 lift and will have a seat pressure in the 115-125 max range per TPIS recommendations in the cam so I feel comfortable in the m handling a heavier valve. Chrome moly seats and retainers etc. Figure on picking up a modest 20cfm at .500 on the intake a even more on the exhaust as he has had a couple of these heads flow tested. For the price it's a good deal for my effort and and the 113 flow characteristics are a great match for the ZZ409 which is a single pattern cam. Then I will have a nice set of ZZ4 heads for sale with only 4,000 miles on them to offset some of the cost. We discussed trying a 37.5 main angle like the old Pontiacs (espoused by Vizard) but I decided to stick with 45 and just do the backcut. Port matching these heads to the FelPro 1204 with the 30 degree backcut should keep good torque down low and help with top end breathing also. Probably run even richer at idle but we will wait until I can finish the project and then run some EASE readings for you before we make any chip changes.

Phil (aka 89ZZ4)