Driveability Question

[KyleQ]

I've got a 74' Bronco that I've done extensive modifications to and shortly after my EFI swap I had thought I blew a head gasket. I had ~150psi on all cylinders besides 7 & 8 where I had 60 and 100psi

Well - knowing that the heads had to come off I started poking around looking for upgrades. The motor was out of a 87 Grand Marquis and it has around 150K on it - I paid $49 for the 100% complete motor, wiring harness, pcm, fuel pump and Ford wiring diagram for the entire car. Needless to say, I had more money into fluids and gaskets, so this is a budget build with nearly nothing to loose.

I tore into the motor and found that the head gaskets were perfectly fine...


Pardon my redneckness, but I did some rough troubleshooting on the cylinder head and found that I've got a valve issue - I poured water into the intake side of the head and it came right out around the valve-


The cylinder walls look good as well (please ignore all of the crap in there, I really should of power washed before I started)


On to the upgrades - I'm good at finding deals and as a new homeowner I've come to learn I've got to be cheap about some things too (which is against my nature).

I have picked up the following for under $250 total.
Iron GT40 heads - kissed a valve and need a little R&R
Explorer TB
New distributor
New coil
89 GT wiring harness & PCM (being stripped, cleaned, re-pinned and re-loomed)
69' 351W manifolds (larger than the 74' manifolds - going this route as any non Bronco specific header dumps into the frame rail)
E303 cam

That last item, the E cam is where my question lies- the cam is rated from 2500-5500 and I know that is where the cam will mainly make power, my question is what does the cam do before that?

If it isn't obvious, the Bronco is a trail crawler and normally low end torque is the name of the game when it comes to 4x4, but I've got DEEP gearing (105:1 in low range) which means I'm nearly always into the middle to high RPM's...

Not ever having a motor with a different cam I don't know what to expect - will it bog down low not run correctly? Could someone post a dyno sheet that has GT40's and a E cam?


I'm really thinking this will give me what I want for mid-top end power - I'm thinking that if I can't get the motor to pull enough to do what I want, I can always drop into a lower gear. Nearly all of my gears overlap- I'm running a NP435 4 speed mated to an AtlasII 3.8:1 with 4.11 gears.

I appreciate any input- I know enough to get myself into trouble...



I've got another 74' Bronco with a half cab that this little gem is going into

357W 10.4:1
GT Tubular Intakes (torque and they fit under the hood)
Trick Flow 185's
Comp XE274HR Cam
MSD Pro Billet with Ford guts
Hooker fenderwell exit headers

[KyleQ]

<crickets> nobody?

[408foureye]

All I can say is you won't be happy with the low rpm performance of that e cam - not for a heavier vehicle.

[KyleQ]

6.69 1st and 3.34 2nd gear - RPM's will be easy to come by. I guess it doesn't matter as I can always grab a lower gear to get within my RPM range...

If I don't like it swapping cams isn't all that difficult, just a timing and lower intake gasket and an oil change.

[Noelsmustangs]

make sure you check valve clearance.. i see no valve reliefs

[KyleQ]

Yeah, a tootsie roll worth the head snugged on skulls work correct?


I've heard clay works well too... What kind of clearance should I have? Minimum numbers?

[Michael Yount]

Min - .080" intake; .100" exhaust; to feel really safe - .100" intake; .125" exhaust.

You may be able to do better than that cam choice in your low compression block. The E would really like a good bit more static compression to work well. If I were you I'd invest a few bucks and have one of the cam gurus model your set up and recommend a cam. We picked up 40-90 lb-ft from 1500-3500 rpm by pulling the E out and putting in a something designed to make more torque lower with 9:1 compression. Huge difference in drivability. We lost about 15HP at peak. Well worth the trade.

[KyleQ]

Thanks for the clearance numbers - I'll look up a proper way to check.

As for the cam I totally understand that it is far from an optimal choice, but I've got it, money spent and there is always room for improvement. This was a budget build to the max, I'll have less than $600 into a motor swap, fuel injection swap, serpentine swap, custom PSC power steering install, fuel system, head swap, cam swap, Taurus fan install, exhaust rebuild and Mustang PCM and harness install....

I've been breaking parts with a clapped out 302 with a 4bbl 660 on it no problem - I honestly don't think I'll need more power. Take a look at this video - you will see that I stay in the upper RPM's quite often. Devil's Delight - YouTube

Nothing is ever totally built, this will get me by for some time - I may look into a different cam or just build another motor with actual performance parts

[Michael Yount]

It's not a question of "more power" for your application; it's more torque lower in the rpm range.

You can use clay to check clearance to the piston and radial clearance between the valve and the valve relief 'eye' -- clay is the only way to check the latter. If you know you enough radial clearance, you can use the drop-valve method of checking clearance without removing the heads. Be sure you temporarily make your lifter solid before running your clearance checks. Otherwise the plunger will be depressed throwing the measurements off.

[KyleQ]

Alright - clay it is.

The heads are off and going to a machinist - so I'll be using clay, the old gaskets and full torque to see what I've got. I take it I only need to check one cylinder?

For converting to hydro lifter to solid, can't I just take one apart, flip the plunger over, put the top back on without the spring and run it? I guess I'll be making two of them so I can check the intake and exhaust in one run...

[Noelsmustangs]

check four corners.. You can also take the snap ring out take the plunger spring out and replace it with a soild piece.. ive seen people use lead solder, hard blok, cut off steel dowels.. whatever.

[KyleQ]

Well, the motor is junk now. I pulled the oil pan and found a bunch of big chunks and everything was magnetic. Here is a shot of the pan- I had less than 30hrs on that motor since I put the pan back on it...


No big deal, I picked up a 94 351W and tore it down last night -

Everything looks good, going to the machine shop soon - more cubes FTW!

[KyleQ]

Well, every story needs an ending, so here is mine.

I bolted on some iron GT40's with a fresh valve job on the 351W, rebuilt all of the lifters and fuel injectors and did a bunch of sand blasting and painting.


I wired up the 89' GT harness and it fired right up, makes great oil pressure and runs hard.


Talk about a stuffed engine bay!