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[Panoz Paul]

Good Morning Mike ... I down loaded the cam spec. sheet & will be calling Ford's Tech. Line for complete head specs today ...
1-800-FORD778 / option #2 ; If my current cam is a B or E 303 do you think the 1:7's are a go and are the existing valve springs OK w/ the additional travel / compression ??? Thanks / Paul W.

[PanozDuke]

Originally Posted by Panoz Paul

Good Morning Mike ... I down loaded the cam spec. sheet & will be calling Ford's Tech. Line for complete head specs today ...
1-800-FORD778 / option #2 ; If my current cam is a B or E 303 do you think the 1:7's are a go and are the existing valve springs OK w/ the additional travel / compression ??? Thanks / Paul W.

Yes, I'm sure they will be. You should double check with Ford Tech, but in a prior life I managed a Ford oriented performance shop where we routinely installed the 1.7's with the B303 and never had to flycut the pistons or change springs. As I recall in the early '90's, Ford had a more aggressive cam than the B with about .540 to .560 lift and maybe 230 duration. Springs and flycutting were required to use the 1.7's with that one. Apparently not enough were sold with all that hassle and they dropped it. I have recently installed 1.7's on a '95 Mustang 5.0 motor with the E303 cam and Edelbrock Performer 5.0 heads (1.60 exhaust and 1.90 intakes) with no issue. Duration is 220 and valve lift is .527 with the 1.7's. Runs great. Small increase in the idle rumble (great sound), gained slightly in mid and top end at no noticeable bottom end loss. With the stock heads the net gain on the top should be noticeable and midrange should pick up as well.

The stock valve springs should be fine if they are close to spec. If you want to check them, pull a couple and have them checked by a shop. You know the rope trick to keep the valves seated? I don't use the compressed air technique, too prone to problems. The stock heads don't flow enough to make added power above 5500 or so, the 40p's might do marginally better. A stock 5.0 peaks horsepower at 4800-5200, but the factory rev limit is 6150 on the mustang, don't know on Explorer version, but it's set below any spring issues. Shift at 5500 and you'll have no issues with stock valve springs and that will be about or just above where your peak power is. An occasional minor over run should be OK. The rev limiter in the computer helps, but nothing is going to help with a 5th to 2nd down shift, 1.6's or 1.7's. The most noticeable gains will be 3500 and above. Expect maybe 8-10 hp or a little more and it's useable.

If Ford has any conflicting info, let me know so I get it right. I have some historical parts package lists we used to use in the early '90's I can dig up and reference in the case I've had a major case of brain mush. You might find the Ford tech guys don't have much specific on this combination as they want to sell heads more than rockers as well as being more current in mod motors.

I found those Crane 1.7's on ebay new for about $180. I wouldn't buy them used as they might have been in a cobra motor for 10 to 15 years. I don't think they are economically rebuildable.

Not to change the subject, but if you have any issues with cracked exhaust manifolds, replacing them with a set of shorties will gain you about the same as the 1.7's, maybe a couple more hp. I mention this as the stress on these is greater than in the passenger car due to the exhaust routing and if you ever need to replace them, it's a performance upgrade for not much extra cost, especally if you can round up a gently used set. Makes a nice compliment to the cam and rockers with stock heads. The three together would net about 35 hp or more, with a broad power range. You could be at about 280+ at the flywheel with the intake and the rest, 240 + rw. You should dyno for a good baseline prior to changing heads. With the these changes, a good set of heads, like AFR 165's, and tube headers, like the GTTS Hedmans, could net 40 hp as a next step, without touching the block. I'd bet you'd be pushing 300 at the wheels versus 200 for the bone original set up. My guesstimate only, but it would be very instructive to know as you progress.

Mike

[Panoz Paul]

Mike , Ford Racing stated that the following piston / valve clearence is required ; .080 intake & .100 exhaust ... They recommended pushing the valve down to contact ; then do the math up from there ... plus , never over .500 w/out verifying ... This is a have fun / go drive thing for me ... I'll be safe & go w/ 1:6 's Second thought !!! Measurure the push rod throw ; do the math ... Compair to the .500 " no-check warning ... Call the bubble ... I wish we had more insight to the 2000 Explorer engins that the GT-Ra's have to compair to your / Mike's early Mustang engines experiance ... If I'm Chicken SH** ; let me know !!!

[PanozDuke]

Paul,
The clearance numbers are good. Same as I recall. I believe I checked my motor the way they stated and had plenty with the 1.7's. The Explorer motor should have the same pistons and chamber volume, so the clearance issues should be identical. But I wouldn't take a chance unless I had expert witness that it is the case.

It is a bit of a hassle to check the actual clearance with heads on, but it would give the certain answer. If you decide to do it, remove the rockers on the intake and exhaust valves on number 1, rotate the motor to number 1 at top dead center (TDC) or pointer to the dampner zero degrees mark, remove the springs from number 1's intake and exhaust valves and reinstall the rockers. Allow the valves to ease down to touch the top of the piston and measure the clearance between each rocker tip and the valve stem tip. Remove or back way off the rocker mount bolts so as not to collapse the hydraulic lifter as you turn the motor over one turn and likewise secure the values in their seated (upward) position so they do not drop down into the chamber as you rotate the motor. Rotate the motor through one revolution back to TDC. Reinstall or bolt down the rockers and repeat the clearance measurements. The least valve to piston clearance occurs at the TDC positions so if these clearances are all greater than those stated by Ford, you are good. You can reassemble. If you do this using the original 1.6's before you spring for the 1.7's (a good idea), then you need to reduce the measured clearances based on the greater lift the 1.7's will provide. Multiply the measured clearance by .9412 (1.6/1.7). This gives you the appropriate reduced clearance as if you had a rocker ratio of 1.7 rather than the 1.6. Probably need some help to manage the turning over of the motor and keeping the valves up.

If you think about it, that's a lot of work (couple of hours the first time) for a difference of 8-10 hp, plus the cost of the rockers. Under the circumstances, I'd probably stay with 1.6's, too.

I do have a set of bolt down Motorsport 1.6 roller rockers (blue annodized) I don't need. They had less than 10K miles (probably more like 4000 miles) of use in a street car that never turned over 4200 rpm (screwed up rev limiter, it's a long story). They are in tight, new condition. One or two have a mild rub from the valve cover. The steel covers we have shouldn't rub like the aluminum ones did at the front or rear bolt bosses. I have a partial set of shims that come with them, but they were installed without any and worked great. You can stay with the factory rockers, but the roller rockers reduce friction and oil temperature in the motor and valve train wear. No measurable hp gain that I know of in mild applications. It's really a minor effect. If your interested, PM me: $50 plus shipping.

Mike

[Panoz Paul]

Mike , Yes I'm interested ; I'll take the friction loss & additional stabilization to the valve train by installing the 1:6's that you have ... Every thing points to pedistal type ... I'll get to the car this week end to verify ... Call me / 218.393.4848 to do the deal ... Duluth ,MN . for estimating the shipping ... Thanks / Paul

[PanozDuke]

I'll try to call tomorrow or Sunday. UPS is best so I'll find out about shipping Monday.

Mike