Well, I'm considering heads. .030 over 327 w/isky cam 232@.050 .485 lift, forged flat tops, 461 double bumps. I've been looking at the Brodix race rite 180's. What do you guys think? I know I'll have to rev. it, but these heads have gotta perform better across the board.

I know guys run 180 cc heads on the little motor fine, but I am of the opinion that GM got the little bugger almost dead-nuts right stock in the 11 to 1 CR. 365 and 375hp motors AND even the 275 and 300hp motors at about at 10.+ to 1 CR. too with only like 160 or so cc heads!!!

Therefore, I figure a 170 cc head is probably perfect and a 180 just a tad big.

As always, jmho..

Anyway, if you want them, GET THEM!! You will be fine!!

pdq67

Yeah I think the Edelbrock RPM's are about 170. I'm not totally sold on them though.
I'm trying to look at other aspects of the head too. I believe chamber shape has alot to do with power prodution. I'm pretty sure Brodix has a CNC option for the chambers, but have no idea what it costs.

Whitey,

This might sound stupid, but I honestly figure that a reworked set of Vortec's with their newer, fast-burn, but older, smaller chamber cc sized and 160 cc or so intake ports are a very good CHEAP combination for a 327 based motor!!

AND I'm old-school from the git-go so this runs against the grain of "double-humps to the end!!"..

He, He!!

Sucker with no more than a CC 270 S up to an Isky Z-25 or Z-27 solid lifter cam and it should run like a "scalded-dog", imho..

Please notice I said, "SOLID CAM" here b/c the little bugger will rpm as high as you have nerve enough to hold your foot in it!! WITH good valve springs, of course!!

My junk301 with NO more than the old GM stock -097 Duntov solid cam would go 7500 rpm as well as my long gone Crippled Buddy's 375hp/327 FI motor with the Z-30 Isky solid cam would pull past 7200rpm !!

Been there, watched the tach and done it!!

pdq67

I've read your stand on the 327 before and couln't agree more. I have been considering a solid stick based on what you've said. I'm going to check out Isky's site.

HOLY CRAP that seems like alot of duration. I thought 232 @ .050 with a hydraulic was alot, but if it's what it takes then so be it. Do you think a split pattern would make any difference here? ( then again I guess it depends on the heads)

what are your plans for the car? street/strip? more street than strip? My old 327 had KB .100" domes, GM 041 heads with 2.02/1.6 valves and ported and polished using a flow bench and a custom ground solid cam with 248/254@.050 and .530 lift and in a 65 chevelle it ran 12.18@114mph. I have run a 327,flat tops, old power pak heads, isky 280 mega performer intake and 600 carb with a pg tranny and 3.08 peg leg and it ran low 15`s with a hole in one of the pistons from pinging to death. It had a ton of low end pull and had a nasty idle. If you are going through your motor again, i would run a dome piston and keep the isky cam you have and go with the eddy rpms or the 180 race rights and you`ll have a very powerfull motor that will surprice many people. I don`t have as much experience with 327`s as PDQ67 has but I share the love for them. they are my favorite motor and would`nt hesitate to build another one.

Yeah I think the Edelbrock RPM's are about 170. I'm not totally sold on them though.
I'm trying to look at other aspects of the head too. I believe chamber shape has alot to do with power prodution. I'm pretty sure Brodix has a CNC option for the chambers, but have no idea what it costs.

Yea thats what I thought (specs say 170cc) when I bought a set 64cc RPM head for my dish piston 350 but according to August issue CHP they say true intake port volume to be 185cc thats big difference.

Here's the deal about the camshaft duration as I see it..

270 goes with say 10 to 1 CR.

280, 10.5 to 1; and

290, 11 to 1!

Don't pay to much attention to the duration at .050" lift for STREET cams b/c it's the advertised duration that sets the intake valve closing point.

A short advertised duration number and a big .050" number creates what I call a knarly cam that is hard on the valvetrain b/c you gotta run big valvesprings so that the valves don't float!! (Short-lived on the street sorta deal!!)....

I forget what the usual difference numbers are between advertised and duration at .050" numbers are that are used for good powerful, longer lasting street cams but I figure that CC's XE solid lifter cams are about at it!

Mr. Harvey Crane call's this difference "Hydraulic intensity" ("HI") and the smaller the number tells you that the cam creates extremely high lifter accelleration rates which need big valve springs to control the very fast valve actions!

Examples:

A 270/230, 110/106, .465" cam has an "HI" of 40. An aggressive cam, imho!

A 280/230, 110/106, .480" an "HI" of 50, (a decent hi-po cam, imho), and a

290/230, 110/106, .500", an "HI" of 60 so therefore is a mild cam with respect to being hard on the valvetrain, imho...

GM's old stock, hi-po cams have big "HI" numbers AND they are old-fashioned, longer lasting cams b/c they were under warantee and had to last, but yet get up and run too!

See my point here.....................

pdq67

I agree 100% with PDQ's comments on compression. He's right on the money IMO.

I think the 180's will work great. The engine will want to go to 6500 with that cam and those heads IMO. If you can mill the heads a little to get the compression up to just over 10:1 you can pick up some power IMO.

As I recall flat tops in a 327 make 9.5:1 -- a little low for that cam and an aluminum head IMO (but not that bad)

Thanks Eric for the back up...

pdq67

This is great guys. I've wanted to get my comp. up for some time. I'm pulling the motor this winter to do some engine bay maintainance and while I'm at it I'm going to tear into the engine. So....a little planning and help from this place (and$$$) I'd like to put together a well planned 327. I was going to leave the bottom end alone although splayed mains are in the back of my mind. Its a factory forged crank, resized, shot peened rods and balanced (started life as a 275hp model).
As an aside, I was checking the difference in flow rates between the Brodix IK 180's and the Racerite's - they're almost identicle!!! They must have used the same cast to achieve the port shape?!(Although I think the Racerites look nicer). Now checking AFR's 180's full CNC including chambers, I'm temted to go with these instead. The AFR's flow better at all points; they're the same price as the Brodies through Jegs.......aaaargh I'm torn!!

pdq, The cam thoery is great. so the 280 megacam w/232 @ .050 would be considered a good street unit. There is so much to camshaft's it's hard to dercide on the right one.

sschevellefan, It's mostly a street car although I AM taking it to the track when I get the nuts. Probably over to Mission where a few of my buddies race.( means an hour and a half ferry ride, but I gotta do it!!) If I could run in the 12's I would be more than happy. You had a great setup. Again, It's probably the cam the woke that motor up. I'd love to get the perfect grind that would use every possible ounce of airflow for my peticular setup.

You definately do not need splayed mains. The 327 is fine as a two bolt -- shoot, to my knowledge Chevy never made a 4 bolt 327 . . .

A 2 bolt with main studs should be all you need to make 350-400 HP and go to 6500 RPM in your street/strip ride.

Don't overthink your choice of heads ;) I think the Race Rite 180's would work great. there isn't much to be gained (if anything) from the spendy AFRs

Eric, yeah if the Racerites don't flow as quite as well as the AFR's it's probably a good thing with a 327. And yeah, I am definatly over thinking it!! Couldn't sleep last night.....I know I need help...

sschevellefan, It's mostly a street car although I AM taking it to the track when I get the nuts. Probably over to Mission where a few of my buddies race.( means an hour and a half ferry ride, but I gotta do it!!) If I could run in the 12's I would be more than happy. You had a great setup. Again, It's probably the cam the woke that motor up. I'd love to get the perfect grind that would use every possible ounce of airflow for my peticular setup.

Actually it was a mix of compression, a professional port job on the heads, and having the cam custom ground to match the motors specs. It also took some other good parts but it was a great combo. My motor was a 2 bolt small journal with stock main bolts, sj rods with arp bolts, nothing fancy needed there.

I still think keep your 280 Mega, add some .100-.125" domes and run the racerites and you`ll be very happy with that set up.

FYI -- Flat tops and a smaller chamber (or even D dish and a smaller yet chamber) typically makes more power with better detonation resistance then a large chamber with a dome -- anthough the small dome Speed Pro pistons available for the 327 seem to work pretty good.

I'm running flat tops now. I wasn't planning on changing pistons so a mill job might be the way to go.
I would love to put in a lighter piston though.

trickflow has a set of 175cc heads that flow in the mid 240`s and are available with 56cc chembers. My old 327 had KB .100" domes and I never had any pinging problems.

Good idea Anthony -- the smaller heads would probably be killer on the 327 :D

Good idea Anthony -- the smaller heads would probably be killer on the 327 :D

those numbers are with 194/1.5 valves too. I just picked up a 67 elky project with a 327 so I`ve been looking around to see whats available in the smaller runner heads. 327`s are my favorite motor anyway so I`m always looking for a good 327 combo.