Ford 390 FE - Comp Cams - Car Craft Magazine

We needed to cut the decks a total of 0.022 on both sides to true them up. The plate bolted to the block was also used as a reference when setting up the machine used for this operation.

We needed to cut the decks a total of 0.022 on both sides to true them up. The plate bolte

Cam And Valvetrain
To keep costs down, we decided to use a flat-tappet cam and mostly stock valvetrain for this project. The cam is a Comp Cams 306S for the FE, a single-pattern grind featuring 0.640 inch peak lift and 260 degrees duration at 0.050 lobe lift. The matching valvesprings recommended by Comp are the 930-16 springs, which provide about 150 pounds on the seat and 360 pounds full open.

Cam and compression have to be matched for a strong engine, and with this cam's late-closing intake valve, we needed a pretty good squeeze. The engine still had to run on pump gas, though, so we dug out the Dynamic Compression Ratio (DCR) calculator and punched in some numbers. Comp recommends a static compression ratio of 11.5:1 with this cam, and for this engine the associated DCR was 8.1:1. Generally, a DCR of up to 8.25:1 with aluminum heads will still allow operation on pump premium fuel, so we took Comp's recommendation on the compression ratio and specified the pistons accordingly.

The stock FE valvetrain is up to the task for a big solid cam, with one exception: The end rocker arms on the shafts are located on a cantilevered portion of the shaft. Without a support on both sides of the rocker, this portion of the shaft is prone to breakage through the rocker shaft bolt hole. The solution is a set of rocker-shaft end stands from Precision Oil Pumps. These stands will clear all the factory-style valve covers and provide the support necessary to keep the valvetrain together at higher engine speeds and with higher-than-stock spring pressures.

Dale Pelvit at R&R Performance power-honed the bores to 0.040 oversize. Each piston was measured to confirm size consistency from piston to piston, and then the cylinders were honed to match for a precise skirt clearance. Three different sets of stones and one bottle-brush hone were used to achieve the desired cylinder wall finish. Pelvit says, "The surface finish resulting from this technique yields peak cylinder bore sealing and performance with today's modern piston and ring packages."
Dale Pelvit at R&R Performance power-honed the bores to 0.040 oversize. Each piston was me
Edelbrock's Performer RPM heads for the FE feature 427 Medium Riser ports and flow numbers, plus 428 Cobra Jet valve sizes. The heads are available completely assembled or as bare castings for those who would rather add their own components. For our street motor, we started with the assembled set and then swapped in the 930-16 Comp Cams springs recommended for our cam. The springs were a direct replacement for the Edelbrock springs; even the installed height was correct.
Edelbrock's Performer RPM heads for the FE feature 427 Medium Riser ports and flow numbers
RTV castings were made of the stock Edelbrock intake port and revealed a necked-down area just inside the port entrance (pencil). Also, a flat area in the intake bowl was discovered (arrow). The modified port (left) corrects these issues and leads to improved high lift flow from a two-hour home porting effort.
RTV castings were made of the stock Edelbrock intake port and revealed a necked-down area

By Jay Brown

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e-tek
11/29/2011 at 6:45 PM REALLY excellent article. As a long-time CC and HR reader/subscriber, I can't say enough about the great articles and writing. Thanks for this one, I printed it out and taped it to my 390FE project!

Bob406
5/8/2011 at 3:06 PM Excellent article - print more ford fe articles.

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