I'm hoping some of you guys can give me your thoughts on a cam selection for my car:

'65 Impala SS, 327/300HP w/ Powerglide and 3.31 diff. The car is all original, and when I do a rebuild I've decided to use the stock cast iron intake, 580 cfm AFB, stock fuelie heads (1.94/1.50), stock 10.5-1 compression, free-flow dual exhaust but no headers, etc.

I've contacted my two favorite cam makers (Crane and Isky) and got their suggestions; now I'd like to hear what you think.

Isky: Duration @ .050": 208/214
Lift: .435"/.450"
Lobe Center: 110 degrees

Crane: Duration @ .050": 216/228
Lift: .454"/.480"
Lobe Center: 112 degrees

I'm leaning towards the Crane (Part #H-272-2) but my biggest concern is that the cam I select must have plenty of low end torque so it'll be well matched to the Powerglide. If anyone has first hand experience with this cam (it's a popular one) mated to an automatic please let me know how it works out. The Isky is a custom grind and my only concern is that it's a little TOO mild.

Thanks for your help; I'll be looking forward to reading your replies!

Best,

AP

The crane sounds better to me.

Use a Competition Cams Extreme Energy 4X4 cam, Buy the smallest one they make. That 327 will appreciate the extra torque these cams make. The crane you mentioned may be a little big for such a large car with a powerglide and stock converter. I run the Comp Cams Extreme Energy 4X4 in my truck and it pulls 21 inches of vacume at 600 rpm with 180 psi cranking compression @ 9.3-1 static compression ratio in a 355. 206/214 @ .050 with .432/.453 lift. The next size up is 210/218 @ .050 with .447/.462 lift. 111 LSA for both cams. Also make sure of your compression ratio, 10.5-1 out of a 327 with flat top? pistons sounds unrealistic especially if using a composite head gasket instead of a oem style steel shim. My son and I just built a +.030 327 for his Nova, Speedpro two valve relief flat tops, block was zero decked and with a .045 gasket and 64cc heads we ended up at 10.1-1 static compression ratio. If you're using the 4 valve relief flat tops with a standard deck 9.025 with the pistons .020 down in the hole and a .045 head gasket I'd be thinking your comp ratio is nearer to 9.3-1. Just some thoughts here, Bob

Thanks Guys,

Bob, I'll check out the Comp Cams piece you mentioned but as I said I'm actually partial to Crane and Isky; just personal preference. They both make cams with specs similar to that one so I'll keep it in mind. Regarding that 10.5-1 compression ratio, that's what my motor is rated at stock according to factory literature. It's got the double-hump fuelie heads with (I think) 64 cc chambers. I'm not sure as I haven't taken it apart yet, but I think these motors came with the flat-top/4 valve relief pistons. It's very possible the actual measured compression ratio is smaller, so that will be interesting to find out. If it's closer to 9.5-1, maybe that's the reason I'm not getting any detonation problems now!

Best,

AP

ASSUMING you have less than 10.1, I would look more at the Crane H262-2.

A-P,

Having been an avid small block guy my whole life, I will make a couple of suggestions.

First - If the car is still together and driveable - change the rear gearing to at least a 3.73/1. I run a 3.73 w/ 408BBC, it is pretty tame, but a whole lot more agressive than the 3.31. Just that change alone would be equivalent to a 12.6% increase in engine torque. I would do this first and evaluate the performance increase before diving into the motor. Personally, with a 327 and a PG, I would strongly consider putting 4.10's in it. [ 4.10 gear change would be the equivalent of a 23.8% increase in torque - about the same as leaving everything else as exists and dropping in a 406CI motor]. Think about it.

Second - don't overcam the motor. Even though 327's like to rev, the car will be a slug if you overcam it. It may sound real mean at an idle but will be embarassing to drive with no low end power. This is one of those areas where things have changed. Used to be, you had to have a big radical idle to run fast, now you have small block cars running 12's that idle at 750RPM with only a hint of lopey idle.

Good Luck.

I am building a '65 Nova w/ a 327 PG combo, and my basic long block will be pretty close to the 300/327. I can tell you that your compression will likely be more like 9.2-9.5:1 w/ stock flat tops, deck height, and a composition gasket. I think the OEM rating must be for a zero deck and .015 steel shim gasket or something.

Anyway, I would seriously consider a torque converter, as that will be key in getting performance out of a PG in a heavy car.

Regarding cam, I'm thinking anything in the 260-270 advertised range w/ a 110-112 LC should serve you well. With a heavy car, tall gear, and the wide ratio spread between 1st and 2nd, you are going to want to look for a nice flat torque curve in the 2500-5000 rpm range, and look for a converter that will get you up in that range.

Be prepared to spend money on the converter, because there are converters out there that will be very drivable and efficient, yet still flash to ~3000 rpm. You won't buy them for $150 though. smile.gif

With stock exhaust, definitely go dual pattern. If you want a crane, I'd go with the 206/218 cam, instead of the 216/228 one... that just seems a bit large for heavy car/327/PG/3.31 combo, IMO

Consider running a steel shim head gasket to bump your compression if the block won't be zero decked. Also, the two valve relief style pistons are about the same price as the stock style 4 eyebrow. Lunati may also have some cams for you. A solid flat tappet would make a little more power and offer some tunability with lash adjustment.