Oak

Just have about 750 miles on the new motor, pretty pleased so far, I got 18 miles per gallon the last tank with a 370 rear end and a T5 trans.

I am running a weiand stealth intake and a Holley 670. One thing I noticed when driving is (not sure how accurate tach is) when I get to about 4k rpm the motor opens up like a BANSHEE to about 5700 rpms. The motor pulls good all thru the range but like I said its like I hit the nitrous at 4k, wondering about others experiences with their new Ford Crate Motors, Thanks Oak

hightower2011

Makes me wish I had money, haha

Glad to hear you like it though!!!

PaulS

Oak,
That peak can be from a combination of parts that are designed to run at higher rpm than your cam. Intake, heads and exhaust that are designed to run up to 6500 - 7000 rpm will not perform well until the air velocities are at a certain point.

what are the components you used?

Oak

The heads are what came on the factory crate motor, GT 40 heads not sure of of the size, I have a Weiand Stealth Intake, and a holley carb (670) I am not sure of the specs on the cam it is whatever comes in all of the 306 crate motors.

I went with this combo (intake and carb) because I read in classic trucks magazine that this is what combo they used at Westech and the motor ran well and tested out at 350 HP at the flywheel.

The intake really only specs that it is good for power from 1500 to 5500 rpm, and the carb seems to give me enough fuel, I am running a stock fuel pump I am not sure that would matter?

I am taking the motor to my tuner for a day to see what we can figure out, ie get the timing set where everything is good, check plugs for fuel, etc etc, I will let you know what if anything changes, Oak

hightower2011

What size fuel line are you using from the pump to carb?
I ask this because I have a friend with a '66 coupe with a built motor. It's an 11 second car and he had issues with the stock fuel line being too small.

musnicki

I have a Holley 670 as well. Mine does the same thing. I have Performer RPM heads, Air Gap intake and a cam to match. I think that it's my power valve opening at 4k rpms for mine. It's not your secondaries they, if tuned right, should open slowly throughout your rpm range due as a result of vacum. Check your power valve though. Mine is 6.5hg. That could be what is causing a nice surge of power from 4-6k rpms.

I could be wrong too.

James

Oak

This is what I tried to model mine after, I used an MDS ready to run set up instead of the Pertronix distributor set up, I even used the pro lite fuel lines and like I said I went with a Stealth intake instead of street warrior. My hope is our usual engine builder/tuner will be able to make it ALL GOOD, not that its bad that it screams at 4k Rpms, lol

Here is the link to the model motor

http://www.classictrucks.com/tech/10...all/index.html

Oak

Kotobuki

For those wondering about heads/cam, the ford 306 crate comes with GT-40X heads (1.94"in 1.54"ex valves, 178cc in 62cc ex port volumes, aluminum head, 64cc chamber) and a ford E303 hydraulic cam (282º in/ex duration, .498" valve lift, 110º in/ex lobe center)

PaulS

So, the engine is set up to run at rpm well above the cam. Big ports, big chambers and a cam that doesn't get the rpm to feed the heads?

Kotobuki

I would guess that they use the E303 cam because it's the only grind they have that's "legal for sale or use on pollution-controlled motor vehicles." At least that's according to one chart I checked.