I just had a new cam installed and I am pretty dissapointed with the numbers I got. I know they are just NUMBERS but they still have some sort of psychological impact on me.
My ex-boss has a 03 cobra that does about 118 in the 1/4 and he said he feels like I have a good edge on him, but its hard to tell when your in the passenger seat. When I'm in the passenger seat of his car it feels like a rocketship and I need some depends, my car doesn't do that. But I'm never in the passenger seat of my car. When my dad drives it for fun, he just cruises, and trust me I beg him to drive it because he has given me quite a few loans for stuff when I can't afford it at the moment.
Sorry I got so off topic. And its only 7am here! what am I thinking.
What would it cost a responsible machine shop to mill my heads and check for piston to valve clearance, correctly reinstall the pushrods, springs, locks, retainers, lifters, whatever else needs to come off. A shop I had mill the heads a couple years ago installed every spring off by .100 giving me next to no spring pressure, doing all sorts of crazy stuff.
Aside from removing the heads, what would it cost to mill them, check for piston to valve, and reinstall all the parts correctly? I don't need a solid roller motor grenading on me for something that wasn't directly my fault.
My CR is currently 10.14:1, and I really should have milled the heads when the cam swap was done because the heads were removed anyway to inspect the cylinders. I figure I can get to 10.5:1, 10.7:1, I'm not sure, I'd have to play with pat's DCR calc, but the thing HAS to run on mobil/exxon 93 octane.
I said I was going to be all done with this motor but when I got my chassis dyno numbers back I wanted to roll the car into a rock quarry or superfund site.
My boss with the 118mph mustang said his gut feeling is that I am good for 120, and I am hoping for that speed too. But since I refuse to supercharge/turbo the engine, which would be the easiest way for massive power..
What am I looking at for (I may or may not remove the heads, I might just drop the carr off), but remove all the parts, mill them, CC them, check them for clearance, so on and so forth doing a good job?
The cam swap really emptied my wallet for the car but 565 hp out of a solid roller 460 really had my kicking myself, even if it was through the exhaust, mufflers, alternator, etc, but I put down some dismal numbers on the chassis dyno.
I wanted to use the grind UD harold rec'd or the XR286R, but I got the no from the cam swap person. I think this thing can use some compression, 287/291 256/260 .643 CR lift rule comp solid roller.

Sorry for the long post.

matt

Matt,
You are probably looking at two completely seperate operations here. First the machine shop part of the job will be to mill the heads and cc them. Checking valve to piston clearance has to be done with the heads on the engine, so whoever is going to remove and reinstall the heads has to do that part. Most machine shops do not actually work on vehicles. If you wanted my shop to do this job, you would have to pull the engine and bring it to us. That is really the only way for me to check valve to piston clearance.
Along the same lines, most shops that will do this type of work on a car for you will not be machine shops, so they will have to take the heads off, send them to the machine shop to get the machine work done, and then reinstall them. The ideal situation would be to check valv eto piston clearance BEFORE you send the heads out to be milled. Then you have some idea as to how much you can take off without having to flycut pistons.
Now for my personal feelings ... if you are truly at 10.14 to 1 compression and want to run on pump gas ... leave it alone. Even that is pushing it in my opinion.
Hope this helps,

Even with Alum Bill?
I've pulled the engine a ton of times in the car, but renting the equipment and returning it then renting it and returning it to put it back in gets expensive and a PITA, and my garage is too small to keep stuff like that around.

I thought I was good for like 10.7:1.

If its only going to be a pointless exercise, then I'd forget about it now.
I'm just scrambling for ideas on what went wrong with my cam swap.
yes, I know, I didn't run it yet, but still.. My friend has a 510rwhp, 525rwtq 5.0 mustang and cooks, I've driven it and my car and its night and day. I was promised about 510rwhp out of my 454. I thought it sounded too good to be true, but whatever.. The 700 or 800lb difference in weight can't be all the difference here between the motors. 440rwhp is certainly respectable, but alot different when you get promised 480-525rwhp all along. I will not name this garage/machine shop becuase aside from this they do great work and are good people, with good mechanical knowledge. This was just a major slip up on them and dissapointment for me. 500rwhp from a 454 seems like alot, but 625hp solid roller 454, which seems reasonable, using the % theory (which I was told was crap) 625(.8)= 500rwhp.
I know they are numbers and I should be happy with what I have, but this is like the "1/4lb'der "weight before cooking" type of thing.

matt

700-800lbs of weight is huge..thats the difference between an 11.7 and 10.9 car...night and day difference. It will "feel" like 100HP easy

Matt,you need to stop the psychological drama and just enjoy your car :D
..and I'll take for a spin in your own car,and drive it like I stole it..and you will need depends ;) :D


Please,don't waste your money/labor to shave your heads..you will never feel a difference or see anything change..its not like you're going from 9 to 1 to 10.5 to 1 either..

how much rear wheel torque are you making? Whats the overall curve look like? If your torque curve is fat and somewhat flat, you will do better at the track than it "feels" like it will do because your motor won't be as peaky. You'll have a steady pull through a wider rpm range rather than pull like crazy for a few rpm and be be much weaker the rest of the range.
compair your average hp and average torque and you will have a better idea who has the edge. my guess is the little 5.0 doesn't make the torque.

All I read here is rwhp this and rwhp that. What are the 60ft and 1/4 mi times? That's ALL that matters. Doesn't mean squat how much HP you have if you can't put it down. Oh, and those 'little 5.0s' can put up some numbers with spray and or boost. Ask Billy Glidden.

Take the car to the track,don't worry about dyno numbers these are just numbers they mean nothing.You may surprise yourself on just how good it runs in the upper rpm's.But no matter what it runs I'll bet you'll have a smile on your face when your done! smile.gif

Is that not your chassis dyno chart in your sig? Looks like 460rwhp. You at least need to take a few passes at the track before you tear it apart, doesn't make any sense not to. I'm assuming you have an auto trans? Cars with manual trannies, like the cobra, "feel" a lot faster because you get thrown around a lot more.

Anyway, depending on the dyno, even 440 rwhp should get you very close to 120mph at your weight.

Run it. Cobras are pretty heavy, what is his rwhp?

Originally posted by d1_bradley:
All I read here is rwhp this and rwhp that. What are the 60ft and 1/4 mi times? That's ALL that matters. Doesn't mean squat how much HP you have if you can't put it down. Oh, and those 'little 5.0s' can put up some numbers with spray and or boost. Ask Billy Glidden. exactly. I also hear way too much about peak hp, with no other information about average tq or hp, or anything. peak doesn't mean squat other than to impress your friends with numbers. In an all out race car, peak means more, but those cars are setup to keep the engine at or near peak for as much of the run as possible.

This image is my 3 complete chassis dyno runs.

http://www.detroit-iron.com/images/combodyno.jpg

My governor shifts at 5100, which needs to be 6100 or 6200. I am working on shifting by hand by practicing around town (car is so much more fun to drive now that its less noisy) but when I try to do it fast I miss gears by pushing to far, 1-3 or even 1-N. I can't get the hang of it. I can shift a manual better than that !

Yeah I know Chris I am a fuss budget. That little 93 GT weighs like 3200lbs and puts out way over 510rwhp and its torque curve is just as flat as mine. Its not a competition, he is just my buddy, if it were I'd have put a procharger on the engine when I did a cam swap, but whats the point if I won't cage the car.

1/4 mile times aren't going to apply to me because I ran a 12.09 last year w/ a 1.85 60' with a cam that made more low and less top end, and I have no safety equipment, and won't cut up an original LS5. I'm already so angry with myself for cutting the dashboard for the radio.
I am going to get to the track between may 11 and 22nd, that is my goal anyway. MPH run on my regular radials.
Also-- I reinstalled my vacuum advance and the dyno tuning wasn't done with vacuum advance hooked up. My exhaust gas burns my eyes which I was told is indicative of a lean condition. Is that true?
I have a welded bung for an O2 sensor but haven't bought the sensor yet. I really should.

matt

Matt,
From what I have seen, 10.5 is too much for todays junk pump gas, even the 93 octane. It can be done with an excellent engine management system (read multi port electronic fuel injection) but everything has to be perfect. One mistake with cam selection, or ignition curve and you get into detonation. Also, I dont think the extra half point of compression will buy you that much. Before you change anything, you need to get some passes on it at the track. I bet you will be worrying more about getting it to hook up than you will be about more power.

Thanks for the input Bill, I didn't realize things were so iffy with pump. I see what seem to be alot of people running 10.5-11 and run just fine. I know its only worth a tiny bit of power anyway.
I am looking forward to the track, but hooking up will be pointless, not going to hack with a cage a legit LS5...

Thanks,
matt

This is what I was going to post but now I am backing out of it b/c I am wondering just how far off you are from the "BSE" combination??

And we all know how it runs even if we don't agree with Ed's attitude on the Boards.. AND I'm not going there!!

"Can you say 496 AND then leave the original motor spec's alone when making the .060" overbore and 1/4" longer arm conversion!!

Power will go up and rpm's will drop some due to the arm's ability to make more grunt lower down with the same cam..

Let grunt move you sorta deal but since you aren't going to race it, what the hey, b/c you won't have any timing slips to tell how you are doing starting out and then improving with each little "tweak"...???

Then if you want you can spec your pistons to up your CR. by say 1/2 a point, BUT personally I would stay right at 10.00 to no more then 10.25 to 1 CR.!! Even with aluminum heads...."

How much trouble and parts changing would you have to go through to better match a BSE combination that builds great midrange to upper midrange grunt?? That may just be the key to your dilemma(Sp??)...

Would it be just a change to a smaller cam to move the torque peak down to a lower rpm which should up the area under the torque curve and thus more grunt????

pdq67