Hi folks, I've only been registered on this forum for a couple of days but have previously read quite a few posts as a guest, and am now looking to get some advice on rebuilding my engine in a 1972 Ford Ranchero GT.

The engine is a 460 (bored .030) with 4 bolt mains, code D0VE-A and D0VE-C heads. It was previously built (not by me) with a 268 Comp Cam, Edelbrock performer intake and 750 carb, headers, free-flow exhaust, and electronic ignition. I lost the oil pressure a few weeks ago and pulled the engine because I wanted to change the cam and also check other internal components and inspect for any damage.

The engine has TRW forged pistons (dished 22cc), .010 deck clearance, 75.8cc heads, which have been fitted with adjustable Comp Pro Magnum roller rockers. The exhaust valve has been changed to CJ/SCJ specs at 1.725 but the intake remains at 2.084. There were some small scratches in the crank journals so I had the crank turned .010 and will be replacing main and rod bearings. Everything else in the engine is super clean and in good condition so the only other things I'm planning on doing is honing the cylinder bores and installing new rings because the ring end gaps are slightly out of specs, changing the cam and lifters, and installing a new hi-vol oil pump.

The CR on this engine is approx 9.5:1, and I have been able to run it on 91 octane gas, but it was on the edge of detonation at optimum timing. I also had some problems with hard starting when the engine was warm, especially if I attempted to start it within a few minutes after driving for a while on warm days. It also experienced vapor lock/fuel percolation on warm or hot days.

First question: I've read that the only four bolt main blocks were 70/71 CJ and SCJs but my block has "460" cast into it on both ends of the block and inside next to the bottom of #4 cylinder. This has nothing to do with me rebuilding the engine but I'm curious if anyone knows why a 4 bolt main block would have 460 cast into it?

Second question: I don't want to make a race car out of this vehicle and want to keep it driveable but with a little more cam. One of the reasons for the increase in cam size will be to reduce DCR and cranking compression to reduce possibility of detonation and help with starting. I'm currently looking at three cams: First is the Summit K3501, which specs out at 218/228 duration and 503 lift, with a LSA of 114 and an intake valve closing of 38 deg ABDC. Second is the Crane 288-2 with 226/230 dur and 522/530 lift, with a LSA of 112 and IVC of 40 deg ABDC. Third is Lunati's 11603 which has 222 dur and 500 lift with LSA of 114 and IVC of 41 deg ABDC. This Lunati cam is supposed to be their version of the 1970/71 370HP 429. The Comp cam currently installed has 218 dur, 494 lift, and LSA of 110. I'm not sure about the IVC but I think it is around 35 deg ABDC. All of the cams I am considering have more duration, lift, and a wider LSA than the Comp cam currently installed but all should be very streetable. By the way, does anyone have any ideas about the advantages/disadvantages of enlarging only the exhaust valve or whether the increased size should have any bearing on cam selection, ie single/dual pattern?

Third question: I've read a lot about the improvements of combustion efficiency by zero decking the block. Mine is already pretty good at only .010 clearance, but I think the selection of a cam which lowers DCR might enable me to knock that down to zero and still use pump gas. Also, would you get the same benefits by using a .010 thinner head gasket. The gasket in my Fel-pro rebuild package is listed as .041 installed.

Fourth question: Would I benefit from a higher than stock stall converter with any of these cams? I'm currently running a C-6 with 3.91 traction lock, and the fully loaded weight of this vehicle (heavily optioned) is around 4200 lbs.

Last question: I've purchased a 1 inch phenolic carb spacer to help with the vapor lock and fuel perc. I'm also considering blocking the exhaust crossover. Since I live in Florida I'm not too worried about cold weather problems but am undecided about whether to block this off.

Any and all comments, advice, or recommendations on the post above would be appreciated. Sorry for the length. Anyone interested in seeing a couple of pictures of the car can find it in the Ranchero galleries.

Thanks, Chuck

 

First off welcome to FTE.
second on your cam selections, spreading the LSA is going to increase your DCR (less overlap to bleed off compression) The 110lsa you have now is about right look at some of the xtreme energy cams from comp as an example. Adding a little more stall might become neccesary.
I would also look at maybe a different intake if your going to up the cam some to either the performer rpm or a wieand stealth.
adding a phenolic spacer would definatly help on the boiling carb as it does insulate it to some degree from the engine heat, and blocking the exhaust crossover won't hurt you expecially living down south. (actually it will help you)
Sorry me answers are a little short and not well researched tonight just wanted to get you started thinking before i head to work, but it will give you a few things to look at anycase.

 

I appreciate your feedback but am a little puzzled by your statement that spreading the cam LSA will increase DCR. I'm no cam expert by any stretch, but I did do some research prior to posting so let me explain what I thought I found and maybe you can set me straight.

All of the DCR calculators that I found (3 or 4) on the web stated that the only cam value needed to calculate DCR was the Intake Valve Closing ABDC, and that a later IVC value decreased DCR. As a matter of fact the IVC is the only cam value asked for in any of the calculators I found. I pulled the manufacturer stats of several cams that looked interesting for my application and invariably found that the IVC point was later on cams of similar duration/lift if the LSA was wider. I subsequently input this information along with internal values for my engine on some of these on-line DCR calculators and the DCR values were, in fact, reduced for cams with wider LSAs. For example, for my engine with a static compression of 9.6, the Lunati 11603 with a LSA of 114 has an IVC of 41 and calculated to a DCR of 8.149, while the Crane 288-2, with a LSA of 112 has an IVC of 40 and calculated to a DCR of 8.2. Not a lot of DCR difference between the two cams, but since the Crane cam has a significantly more agressive grind, you would think it should have less DCR, but it doesn't. Both of these cams have significantly lower DCRs than the 268 Comp cam I am currently using, which has a LSA of 110 and IVC of 35. This calculates out to 8.444 DCR, and the Comp cam has the same intake duration of 218 that the Lunati has. One of the calculators I used also shows cranking compression values, and these values were also reduced in tandem with the DCR. I also ran several other cams that were similar grinds except for LSA values, with similar results.

If a wider LSA increases DCR then I must be missing something in my calculations, so I hope you or someone else can explain it to me because one of my main goals in changing my cam is to select one that will give me a reduction in both DCR and cranking compression. I'm also looking to keep good drivability while hopefully gaining a little more performance than the Comp 268 I've been running. I was really leaning towards the Lunati cam before your reply, because the calculators I ran it through looked like it would bump up the performance a little while giving a pretty good reduction in DCR and cranking compression, but now I'm thinking that I might be overlooking something so maybe someone can help clear this up for me.

Appreciate your thoughts or comments,
Chuck

 

forgive me for bieng backwards, yes it pushes the intake closing point farther into the compression stroke bleeding off compression. Don't ask me what I was thinking last night I was tired and in a hurry sorry. Actually I was thinking overlap for some stupid reason, and I am not really sure. I hate to give misleading or bad info.
But I still don't like more than 112 on a 460 stroker motors need more but your dealing with more cid and usually more duration and overlap so look for a cam with around 220 at .050 maybe as high as 224 and keep the LSA between 110-112 the comps xtreme 4x4 cams for example have a 111lsa. That duration will like a little more stall but you already mentioned that, and a 2000-2200 stall should be great with it. The biggest problem I have with the lunati cam you mentioned is that its a single pattern cam, in other words has the same duration intake and exhaust and big block fords need more exhaust as that is the big restriction on them, even with the bigger valves than stock it's gonna want more exhaust duration. which also won't hurt the perfomance of hte engine.
Another option to drop DCR is to retard the cam timing 2 degrees that will put the intake closing 2 degrees later. Down side is it will move your power range up about 50-100 rpm but you won't really notice that much.
One other thing I noticed all the cams you listed and the ones I would look at will have over .500 lift and thats pushing it for stock springs so if the springs haven't been replaced or your not sure, that should be on your list also.
Oh and on the block, what is the actual casting number above the starter. The factory 4 bolt blocks are almost always DOVE, although it's been reported that some are D1VE but those are few and far between. the 460 cast into it does NOT mean that block was originally a 460 remember that 429s and 460s use the same block, and even the 4 bolt blocks are the same as the 2 bolts with the DOVE-A casting just modified a little (Boss 9 blocks are actually different in some ways for hte oiling system but the outside of the block is the same for the most part also)

 

Thanks for clearing up the LSA point.
The casting number on the block is D0VE-A. I was just curious as to why a block that was supposedly built only for 429 CJs/SCJs would have "460" cast into it, but maybe it isn't that uncommon.
As far as cam selection goes; I looked at the XE 4x4 Comp Cams and the problem I have with them is that the X4262H has a lower IVC than even the 268 I'm now using so it would actually increase my DCR, which I certainly don't want, and while the X4270H has an IVC slightly higher than my current 268 it is still lower than any of the other three cams I listed so would still have higher DCR than those three and with a 226/234 dur and 554/574 lift is more cam than I need. In general, most of the Comp cams that have durations in the range I'm looking for all seem to have more lift than I want, and most seem to have an early IVC, which tends to increase DCR, and is one of the things I am trying to get away from. I do have dual valve springs but still don't want to get too radical with the lift. The most I was considering was for the Crane 288-2 which has 522/530.
I used a program called "engine analyzer" from Performance Trends to compare some of these cams and these are the numbers I came up with for my engine:
Cam Pk torque 2k torque peak HP vac DCR Cranking Compression
Comp268 497 443 468 16.2 7.4 187
Crane288-2 496 414 482 15 7.08 175
Summit 504 426 475 16.3 7.29 179
These HP and torque numbers all seem a little on the high side to me and the DCR is off considerably from the DCR calculators I used, but still the numbers are useful for
comparisons. The vac figure for the Comp 268 is right about what I physically measured on my current setup, but can't vouch for the other figures. Unfortunately, I only had a ten day trial of this program and didn't know about the Lunati cam before the trial ran out so wasn't able to compare it, but aside from the single pattern (which is also the case for the Comp I am now running), the specs look pretty good. Based on the IVC, the cranking compression and DCR should be lower than any of the three above, and while the wide LSA may have some drawbacks, it doesn't seem to hurt performance that much and seems to significantly improve vacuum and idle quality. One thing in favor of the Summit cam is that I can get the cam and lifter package for $81.95 and I believe this cam is ground by Crane for Summit so the quality should be ok. Anyway, I have some figures to work with and will make a decision pretty soon because I want to get started on this build and get the car back on the road.

Thanks for your input. I appreciate having the opinions of people who obviously have more experience with this engine than I do. My other collector car is a mildly built 1968 SS396 Chevelle (maybe I shouldn't mention that on a Ford forum) which I've had a lot longer than the Ranchero, but I actually prefer driving the Ranchero.

Chuck