Comparing the flow numbers (Intake/Exhaust)
Lift	Stock 5.0 HO	GT-40X	Ported E7TE(Thumper)	Dart SR
.400	144/105	202/149.4	196/150.5	185/129
.500	156/108	216/149.1	218.9/154	205/141
.600	169/111	214/149	219.9/160	N/A
flow numbers for comparison only Thumper Ported E7s flowed on SF-600 Super Flow Bench @ 28 in H2O with NO Exhaust Pipe and 4.030 Bore fixture

Most roller cams are around .500-.545 lift. After the cam lift the additional flow isn't needed. Most roller hydraulic cams stop HP at or about 6200 RPM. NOS is all exhaust friendly and flow figures aren't that critical, as the NOS is in effect a supercharger. The low lift flow numbers are the torque builders. The faster the air starts flowing at extremely low valve lift is the key to filling the chambers. A correct 5 angle valve job, and bowl work (smoothing and blending) are far more critical than high flow numbers on a 6000 RPM small cubic inch engine.

Port and bowl work has always been the way to make horsepower. That is on any head!!! THUMPER ported E7s will allow low 12s and be friendly with header, rockers, and fuel requirements. With a power adder (NOS for example) the low 11s or high 10s are within reach.

I offer E7s that have been ported where they are needed the most. The exhaust port is matched with a Mr. Gasket "Soft Seal" header gasket, and ported all the way to the bowl, straightening the upper port, removing the EGR bump, and lower exhaust valve boss. Then the exhaust port is polished to the bowl. I gasket match intake port iwth Felpro 1250 gasket, and blend in to the bowl. Both exhaust and intake bowls are "pocket ported", smoothed and blended removing sharp angles, and attention to the short raius, with exhaust bowl polished. A 5 angle performance street valve job is done to increase low lift valve flow, to allow the cylinder to fill with air as the valve leaves the seat. The correct port size allows incredible throttle response!!! The heads are cleaned, tanked, magnafluxed, surfaced flat, and assembled ready to bolt on. Springs are set to carry a .500 lift cam *see below for additional services.

Related articles worth reading...
Car Craft November 2000 - a 95 stang in the 12x...with stock heads (E7s NOT ported)
Car Craft February 1998 - 400 Horsepower on 302 cubes and ported heads
MM&FF April 1997 - 8/10ths off ET on ported heads
5.0 November 2000 - Having our heads examined

Note: Be real with yourself. Ported E7TEs will allow 12 second ETs!!! With power adders, low 11s or high 10s!!! Thumper Performanceheads $595.00 + $100.00 (Refundable) core and FREE Shipping* So spend your money wisely.

A comparison of horsepower*
	3000 RPM		5000 RPM		6000 RPM
Head	Torque	HP	Torque	HP	Torque	HP
GT40X	298	170	275	262	219	259
Thumper Performance	297	169	279	265	233	266
Stock 5.0 HO	302	172	246	235	182	208
*compiled from alternate sources Horsepower and torque is from a stock 87 5.0. The numbers are with a stock cam, throttle body, and intake -- NO BOLT ON'S, and exhaust adjusted to performance mufflers and exhaust pipe diameter

Home ||  Headflow ||  Valve Size ||  Porting ||  Ford Head and Cam combos
Mini Ported and Polished Heads ||  Frequently Asked Questions ||  What our customers say