Thread: 327 Build Cam Selection

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Your best Power #s H.P and Torque come from the XE268H . As for your C/R if you have Flat Top Pistons even with 64cc Hump Heads on that 331 it's under 10.1 might just be under 9.75.1 and you can run the .038-.042" Fel-Pro Gaskets to drop it just a bit more and run 89 Octane Pump Gas . But with out doing cc-ing we are Guessing . I have a 327 with small Pop Up Pistons that is right at 10.1 .

cc'ing came in at 62cc. I was told that resistance to detonation was made with good quench at .035" to .045".
The SCR calculator's I use with 4.030" bore, 62 CC, .015" in the hole, .024" head gasket, 5 CC valve relief, etc..
come back at 9.9 to 10.03 depending on the calculator(theoretical I know). I suppose I could run a thicker gasket but I thought quench was important also?

Using an .041 gasket instead of the .024 gives a quench of .056 vs. .039 with .015 in the hole.

Using CamQuest:

Comp 280H@ 10.03:1 368 HP @ 5500 388.7 TQ @ 4000
Comp XE268 @ 9.63:1 364.7 HP @ 5500 395.7 TQ @ 4000

Using the 10.03:1 SCR and 7.9 DCR with a good quench gets a gain of 3.3HP and a loss of 8.3 ftlbs of torque
vs
9.63:1 SCR and 7.93 DCR with a bigger quench.

The 280H setup is supposed to be safer with an ever so slightly lower DCR but a quench in the range of .035 - .045.

I fully realize these are computer generated numbers but they are calculations not guesses. I wish I had a program that could show me the losses with the 280H cam at 2500-3500RPM vs the XE268...

how are you getting your CC numbers your head been CC? what are you basing you CC of your heads gaskets off ?felpro f1094 tin shim .015 thick CC 3. f1003 bore 4166 .041 CC 9.1 .... Rol Gasket steel shim hg31600..4.150 .025 CC.5.4 ...hg31000hr 4.175 .039 CC ..8.7 ..hg1000ht 4.175 .045.CC 10.1 . getting the deck set right on the money is a big deal i deck all the engines i do with the BHJ true deck blocks can be off alot but first you need to know what you really have

cc'd 4 chambers with an average just under 62. Block has been decked and all 8 piston depths measured. Lowest measure is .014 and highest is .0165. Was planning on using Victor Reinz .024" to give me .039" quench.

The gasket I used in the example was a felpro 1003 which .041 compressed.

Sure correct quench will make max Power . But if you can't run it with the Timing were it should be or have to run racing Fuel in a Street car what good is it . Put the Fel-Pro .041" Gasket run the Timing up and use that XE268H with Pump gas . And with that # matching intake run a 1" 4 Hole Spacer to make it work better . And that Holley you have will need to be full trick out . That Joker will run it's azz off if you put that Engine Together right .

I highly doubt Pat would suggest the O/P to do that.Just too many yrs as a professional engine builder.

No I would not expected Pat or any Engine Build to say quench is not important . And it's a Holiday weekend don't want to be baited in to a Fight with Pat . Yes he has a good Head on his Shoulder with Building Engines this Post is not here to Test him in any way . Because I am sure from the start he would not have Built it Like it was Built .

Ok Now that we have that cleared up . Now the other side of the Coin is this . This Engine is basically done and the owner has said he does not want to divert from the way it is . Yes he is willing to make a camshaft change . But The Heads and intake / Pistons are staying . So to make what He has more usable and more affordable to run . I would go with the thicker Head gaskets . You can show me all the math and number on how it's so wrong . And I can tell you I have built many that same way that ran just fine . You know how many Muscle Car got thicker Head gaskets when the Gas shortage kicked in Lot's of them . And most ran just as well and on the next Lower Grade of fuel . One other way to knock down the cc's is to open up the chamber more then he can use the .024" Gaskets he has and have better quench . Most of the Time there are many ways to get around Problem with Engine Builds .

Thanks for all the info guys...it is much appreciated.

I already run the 1 inch spacer you mentioned and my Holley 600 is going in to a highly respected carb tuner next week.

This engine was in my car before the rebuild. It ran with the same externals, an L79 clone camshaft(lets say .292,.292, .221,.221,.447,.447,114) It would have been 64 CC before the heads were cleaned up. Pistons(Nylen cast) were in the hole .028, pistons were 4 valve reliefs, not 2 like the ones I'm using now, 6 cc vs. 5. Gasket was an .041".

SCR was 8.9 and DCR would have been about 6.8. It was a touch soggy below 2000 but actually ran strong.

I guess I was trying to get everything to line up so to speak numerically by picking a camshaft that worked with the SCR I had after the surfaces were cleaned up and the quench height was optimized.

Just watched this. Similar build to mine only 292 adv dur vs the 280 was looking at. Same .050values and lift. 108 vs 110 LSA.

http://www.youtube.com/watch?v=qUw50FUC80A

The 108 L/S Camshafts do help Mid Range Power Lots of Roundy- Round cars run them they also reduce Idle quality and Vacuum . I have ran a 450" Lift Cam in both a 327 and 350 with a 108 L/S . They seemed to have a shorter Power Range then the 454" 110 L/S Cams that I have used . The 454" 110 L/S also Idled better with need added Vacuum for power brakes . I Know you have manual Brakes but Lots of car's don't . You can see all the H.P and Torque #'s with all the Cams plugged into your Build info in this Post . That L-79 Camshaft will not make the Power the XE268H or 280H will .

I built this Engine a short Time ago . I used parts I had Left over in the Garage and some new parts . It's a one Piece seal 5.7 350 Truck Short Block with Dished Pistons that I was barely able to clean up the deck to reuse . So I was not going to try and run thin shimed Head gaskets on it . It has milled and Ported #882 Heads the quench is not so good it has 8.5.1 C/R but I ran a Camshaft that will not blow off cylinder pressure . The Intake is also a Left over Part not the best match of parts ran a New set of Summit Long Slot 1.5 stamped rockers . My Point is this I can Run this Engine all day Long on 87 Octane Fuel and it seemed to also go easy on Fuel when Breaking in and Test ran and it still will make around 350 H.P 405 Torque .

5.7 Test run #2 - YouTube

Off the topic a bit but what spark plug would you boys recommend since you know my build?

I should log in more often. I'm thinking about a cam change on my 355 and a 406/407/409 I plan to build in a year or so. Your collective calculations using DCR finally got my attention. I currently run an XE274H but I want to change to a solid lifter cam. I considered this when I did a mild refresh on the short block five years ago. My DCR now is just under 8 and I'm running 72cc Dart Iron Eagle 180's w/ KB flat tops. I can run 87 octane and I can't get a ping. Makes me suspect I'm not getting enough squeeze and I might switch to thinner head gaskets. Since the heads are coming off anyway, should I just get them shaved instead? I know this is a little off the path here for this thread but it's all relative. The car is a '65 Tempest. I have a noisy 3.73 gear getting changed to a 3.55 and a 10" converter, not sure of the stall speed.

The 270 Magnum would be a nice cam for your application. If you want the solid lifter 327 sound then look at the Comp 270S which has specs very close to the old Duntov 097 solid lifter cam except with more lift, .450 net lift. The 270S has the same 224-224 dur. at .050 as the hydraulic version and you can vary the lash between .015 and .030. The Isky 270 Mega cam -221-221 at .050, .465 lift on a 108 LSA would work well too for your combo.

66 nova 327 350 hp rare 4 speed

Resurecting an old thread here as life got in the way and the car finally got finished and on the road. Just wanted to say thanks for the info. Ended up with the 280 Magnum cam and love it. Here is the build:

.040 327
Forged crank, rods and hyper pistons
10.3:1 with .038-.040" quench
Double hump heads, 2.02/1.60 valves, screw in studs, guide plates, roller rockers
L79 winters intake, Holley 600, L79 dual snorkel air cleaner
1 5/8 headers, h- pipe, duals exit behind the tires
Pertronix, 10 initial, 34 advance
Muncie 4 speed
12 bolt 3.73:1 Eaton posi
245/60/14 rear tire

Car idles beautifully at 650-700 Rpm, sounds fantastic. Pulls hard to 5500 for sure(havent went any higher yet,lol). I wouldnt have wanted any smaller of a cam. It can pull 1200 rpm in fourth gear! Running 93 octane

Thanks again fellas, sorry it took so long to give the results...lol