Far too many choices. Basically stock 68 390GT rebuild, alloy intake is biggest change (going w/RPM Performer for weight loss, far less cost then the Blue Thunder).
Now leaning towards Comp XE256H 33-234-4 (available locally, no overseas shipping).
Looks like a mild upgrade to stock and a minor bump on the one I was considering:
Even the XE option is much less than a match for the RPM intake, but will no doubt deliver several more ponies to the rear wheels. Neither will have any "rump-rump". Your mom will drive it happily. Ok - ok, the reality (for me) is that if I'm going to spend money & time doing a cam change, it MUST have two things:
1) At least a noticeable rump, and...
2) Some horsepower to go along with that torque.
C'mon man, break down and pop for something that will tick off the wife and send rice burner owners running for their X-Box games.
Having said that, my 429 Torino has a very mellow CompCams 268H (218* @ .050) in it. I never drive it anymore. Too mellow...
My Fairlane on the other hand... Well, with 250*/258* @ .050 I love driving that thing, primer & all. Rumpity- rump.
Wayne K.
Goodyear, AZ
- 1966 416 4-Speed Fairlane
- 1972 429 Torino Sport
Richard,
If you can provide this a comparison will be more informative, though the cams are pretty similar it depends on what they will be going into -
68 Mustang S coupe, factory GT. Going back to near original except for these bits and the true trac.
3.25 true trac rear (original gear ratio), original 4 speed close ratio toploader. 69 390 block bored 0.030 over, stock exhaust manifolds and iron heads (yes they suck, don't mention them, they stay), stock adjustable rockers. Performer RPM to lose weight (stock S is suspect anyway), original 600 cfm vac sec Holley, hypereutectic cast dish top w/eyebrow pistons (calcs out at ~10.1 or so for CR), moly rings, C7AE-B rods, stock 2U crank 0.020 under, Clevite bearings, ARP bolts.
Just want to know the difference, if any, in basic STREET driving that would be seen between the two cams. I want low end torque, not max rpm/hp.
This message has been edited by smykayrich on Jul 9, 2008 4:54 AM
if you are truely getting 10-1 compression you need to bleed some of the static compression or you will be detonating. The high compression needs a "wilder" cam and Oregon probably has a wide centerline profile that will give you a good low end pull plus an additional good top end without the detonation problems and too much rump-tee-rump.
This message has been edited by PREMOD70 on Jul 9, 2008 6:24 AM
different then stock to to the 110 center, with ever so slight rump, while the stock is very smooth. The stock cam will be smooth strong power from 800 rpm to 4000.
The XE256 will also pull from 800 or 1000 rpm to about 5000, and by about 1800 or 2000 rpm, the tighter 110 lobe center will make MORE midrange power/torque than stock which will be noticable. And top end will be about 5 to 10% (read that + 15 to 20 HP over stock) but will not be that noticeable because in street driving you never get up that high. Should run well with the XE, but the faster valve ramps "may" make more valve noise to a trained ear.
Depending on car and gear, 268H, 270H, or XE262 are all possible (or 270S). If gas mileage is an issue, stick with either stock GT or the XE256.
************************************
1967 FE 390GT engine: 416 CID 233/238* @ 0.050 Solid Lifter w/ 4 spd TL.
1968 GT/CS Mustang. 289/c4
1995 Mercedes e320 I6 DOHC, 216 HP wagon.
2003 Tundra SR5, 4.7 DOHC, 4x4.
Another Galaxie (one day.)
Oh and a Bicycle - daily driver to save gas for the 'F'un 'E'xcursions.
In my 390, zero decked flat top pistons with 72cc heads and a standard fel pro head gasket nets me 9.75:1. If you area assuming 72cc for stock heads you're probably too low--they're likely closer to 76cc. Add the dished pistons and you're likely closer to 9.0:1.
That lower comp ratio will help you keep from detonating with the small cams that you're looking at.
Got 10.3 based on that plus 0.040 gasket, zero deck (not likely but a guess right now), 4.140 gasket dia, 3.78 stroke, 7.5 cc piston dish, 0.315 top ring gap. Drops to 10.1 w/0.010 deck.
One of the best uses of dyno software is to compare parts, especially camshafts. It will pay for itself with your first cam. Couple the cam with the car's specs such as weight, gears, tranny, converter, etc and the intended use, and the right cam will jump out at you.
Richard,
I think you'll enjoy the build very much over the long run.
I computed the 2 cams you mentioned here and one other.
Through the series of runs I was easy on the clutch figuring your use. Unless changing clutches is your hobby!
First my least favorite, the 218-218 duration:
Torq 400 at 3400
Powr 342 at 4900
2.31 60ft
14.54 at 95.9
My next favorite, the 212-218 comp cam:
Torq 401 at 3400
Powr 338 at 4900
2.29 60ft
14.51 at 95.9
Finally my favorite, maybe cost wise as well, I bet you could save enough to almost buy a 4" crank, well maybe not quite. Depends on your prices over there etc. Anyway here is the 204-214 cam, it is also the closest in behavior to the original 390gt/428cj cam, a little smaller but cut a little tighter:
Torq 407 at 3200
Powr 329 at 4800
2.24 60ft
14.44 at 95.7
The small torq advantage dominates here and this will also be the strongest one if you floor it from 2000.
But the bottom line with these numbers is they are all so close, the car and the computer could easily differ by a tenth or so. So any of these cams would do very nearly the same thing.
I used my "more advanced" but maybe or maybe not better miles-per-gallon estimator on the final combo and got:
11.1 mpg city
18.3 mpg highway
A very enjoyable ride even with pricey gas!
PS I just saw smoak's comment about the 10.0cr and I agree it is right on the edge of getting away with, I think you'll be ok on premium 91 octane. Even on regular 87 octane it will be fine the day you build it, but when any carbon builds up then it will knock on regular.
This message has been edited by werbyford on Jul 9, 2008 6:42 AM
'come on Werby, my 233/238* solid is not sensible? LOL!" ACTUALLY
July 9 2008, 11:43 AM
I must admit i DO have a new melling gt spec cam in my closet, 204-214*, for the day when i get sick of the 232 cam. I can always go back to stock if i want. and i may one day.
************************************
1967 FE 390GT engine: 416 CID 233/238* @ 0.050 Solid Lifter w/ 4 spd TL.
1968 GT/CS Mustang. 289/c4
1995 Mercedes e320 I6 DOHC, 216 HP wagon.
2003 Tundra SR5, 4.7 DOHC, 4x4.
Another Galaxie (one day.)
Oh and a Bicycle - daily driver to save gas for the 'F'un 'E'xcursions.
This message has been edited by TorinoBP88 on Jul 9, 2008 2:31 PM This message has been edited by TorinoBP88 on Jul 9, 2008 2:28 PM
