327 build suggestions

[pshepard327ci]

I am finally to the stage of the build were i need to get all the valve train components and obviously this is a very big deal. This is going to be a street/strip car, its a 240z and i would rather it be close to extreme than close to tame. I have:

 

69 4bolt 350 block 30over

Large journal 327 steel crank.

H beam Cat Rods 5.7

KB Hyper dome pistons (1 cc dome) kb157.30

sealed power rings gapped for the hypers

Double hump heads completely reworked - 2.02/1.6 64cc with rocker studs tapped.

 

I am planning on going with the comp cams 282solid mechanical kit (CCA-K12-223-4), and comp pro magnum roller rockers(CCA-1301-16). Are these the correct studs for those?(ARP-134-7101) or do i need the longer ones? I tried the best i could to calc my compression ration out and im at around 10.5. I measure the piston to deck and i am at about .016.

 

I am all about some suggestions on where to go, i really want a fun crazy car to drive, and this is my first engine build so have the usual second guessing myself.

[Pyro]

I get 10.12:1 with your specs.

 

333cid= 682cc/cylinder

0.016" in the hole and 4.030 bore = 3.3cc

-1cc for dome

8.4cc for 0.039" head gasket

 

(682cc + 3.3 -1 + 8.4 + 64)/(3.3 -1 + 8.4 + 64) = (682+74.7)/74.7 = 10.12

 

With roller rockers you need the longer studs than stock (+0.250").

 

if you plan to use 1.450" diameter springs, the heads will need to be machined.

 

What are your plans for gear ratio, transmission, exhaust, intake, carb, and ignition?

[pshepard327ci]

I am not sure what rear gear i have now, but i will be swapping eventually to close to 3.7 or so.

I originally wanted to run auto but i figure it may be wiser to run manual so i dont need a huge torque converter.

Shorty headers to probably 2.5 dual exhaust.

I havent decided on intake, either victor jr. or the air gap dual plane.

Carb will be a demon 750 or smaller if i dont need that much.

 

That sounds better to be compression wise. I think the heads have been machined already, but may be something else that will have to be done.

 

Overall does that came look like a good match. I do want solid mechanical so that would be one of my requests.

[Pyro]

I would use a performer rpm intake. Not an air gap. An air gap takes a lot time to warm up the carb so in the winter it is a pain to drive. Plus nuts and bolts are always falling into the carb which sucks.

 

I would use a 3.90 gear. Especially with a 327 which will be low on torque compared to a 350.

 

The 282S is a nice cam but you may want to consider a cam with a little more duration on the exhaust side to compensate for poor flowing gm heads and block hugger headers. I think compcam makes a grind in between the 282s and the 294s that is a dual pattern.

 

A 750 3310 holley with vacuum secondarys would work fine. Get some 68, 69, and 70 jets for carb tuning. And maybe a 34, 37, and 40 squirter.

 

A GM T5 5 speed would also be a good choice.

 

A crane HEi for ignition (summit racing) get one with vacuum advance.

 

As for exhaust, I would recommend 2-1/4 off the headers to pair of dynomax bullets then to a Y-pipe then to a single 3 inch pipe then a hooker aerochamber on the end. I recently built a similar exhaust system and it sucked without the bullets. Had to go back and put them in.

 

Should be able to get your 240 into the high 12's at 110 mph with that setup. Would be a fun street car, no doubt. A better set of heads, full length headers, and a little more cam should get you into the high 11's at 118 or so.

[pshepard327ci]

I worked over the heads pretty well and also had my machine shop work them some more so hoping they flow as good as they can. But i will definitely be happy with mid-high 12's that is a great starting point and around were i expected it to be.

 

Do you by chance have the model of the dual pattern cam you suggested so i can take a look and compare. I think the 282s will do fairly well but if the dual pattern takes better advantage of my setup then it sounds like a better fit.

 

As far as the RPM intake do you think that will be able to handle the higher rpm, im not going insane but wanted to be able to take it to 7-7.5k or so if i am feeling ballsy.

[Zerrari GTO]

I worked over the heads pretty well and also had my machine shop work them some more so hoping they flow as good as they can. But i will definitely be happy with mid-high 12's that is a great starting point and around were i expected it to be.

 

Do you by chance have the model of the dual pattern cam you suggested so i can take a look and compare. I think the 282s will do fairly well but if the dual pattern takes better advantage of my setup then it sounds like a better fit.

 

As far as the RPM intake do you think that will be able to handle the higher rpm, im not going insane but wanted to be able to take it to 7-7.5k or so if i am feeling ballsy.

You should worry more about the valve train than the intake manifold if you want 7-7.5K...I see a roller cam setup in your future..and new heads. Go with manual secondaries if you opt for the 5 speed.

[Mike C]

Have you bought all these parts? As usual, no replacement for displacement... I ran a 4 bolt 327 punched .030 in my Camaro for a few years. I ran a Cam Dynamics 284 hydraulic cam and 4 valve relief flat tops (about 9.5:1) With 4.10 gears in a 3400# package it ran 14 teens. Your heads are way better than the bone stock 186 casting heads with 1.94/1.5 valves I had. Currently it resides in my Jimmy, replaced with a 355.

 

The 282s is a great cam. I would run 1.6 rockers on the INTAKE and 1.5 on the exhaust. Small blocks just don't need split pattern cams with even a halfway decent exhaust system.

 

The Performer RPM is a great intake choice as well. 3.70 with 26" tires that a Z likes will be plenty. I just prefer manual trans cars, but an auto with a 3000 rpm converter would be OK for the 282s and the 3.70 gears in such a light package.

[Pyro]

I worked over the heads pretty well and also had my machine shop work them some more so hoping they flow as good as they can. But i will definitely be happy with mid-high 12's that is a great starting point and around were i expected it to be.

 

Do you by chance have the model of the dual pattern cam you suggested so i can take a look and compare. I think the 282s will do fairly well but if the dual pattern takes better advantage of my setup then it sounds like a better fit.

 

As far as the RPM intake do you think that will be able to handle the higher rpm, im not going insane but wanted to be able to take it to 7-7.5k or so if i am feeling ballsy.

 

All the numbers that I have been giving you are based on my 240 V8. started out with a 3.90 gear, T5, compcam 292H, 362 sbc, 10.75:1 cr, heavily workout over double hump heads, block huggers, 2-1/4 duals to 2-1/2 single exhaust, performer rpm, holley 750 3310 vacuum secondarys. ran 12.7-12.9's at 110-112 on small street tires (215/60/14).

 

Then ran some mid 12's at 114 with some better traction tires (bias ply MT) and true duals (cut passenger side off gas tank to make room for another muffler)

 

then added same better heads (200 cc dart iron eagle) and some full length headers and some MT drag slicks (26 x 8 -15). and ran some 11.7's at 120. Broke axles every 20 runs

 

then added a 200 shot n20 and ran 10.7's at 135. broke axles every 3rd or 4th run.

 

Yes, the performer will pull to over 7K rpm. My engine would valve float at 7200 (according to my 5 inch autometer tach). However, my best et's came with 6500 rpm shifts even though the engine felted like it was pulling hard to 7,000. I'm not sure a 282s with rev to 7000 in a 327. You may need more cam

 

compcam makes a XS274s than has duration of 236/242 or have you considered the new 30-30 compcam (12-673-4) 284/291, 247/254, power from 2300-6900.

 

Block huggers are not good headers. Yes, they are much better than manifolds but not nearly as good as full length. But, full length headers are hard to get into a Z. And it is tough to get a good exhaust system under a Z. Furthermore, most all GM heads have poor e/i flow ratio (under 75%). Every performance chevy magazine would say that an engine with a poor exhaust system or a poor e/i ratio will run better with more exhaust duration than intake. Easy to research that.

 

Also, the general run for manual or vacuum secondarys is, auto trans cars do better with mechanical secondarys and manual trans cars do better with vacuum secondarys. The reason is, there is more secondary tolerance with a torque converter than a clutch that locks up. Plus, if you want any gas mileage at all, get vacuum secondarys.

 

I wish I would had left the car in the 12 second configuration (the way was when I first built it). It got too crazy to drive on the street and lost its street car appeal. And it sounded much better with single exhaust.

[pshepard327ci]

Thanks for all you guys help. I think i am really liking the 282s but will definitely check and compare the xs274 and the 30-30.

 

I am leaning more towards manual now but thats several months away and depends how much either one will cost. I will need to re-read the jtr manual, this project has been a long time coming.

 

Thanks again, and i will most definitely have more questions down the road. Searching first of course!!

 

UPDATE: Ordered my parts yesterday evening, hopefully no wrong parts:

ARP-134-7104 ROCKER ARM STUDS

CCA-1301-16 ROCKER ARMS RLLR 1.52 3/8 SBC

CCA-4808-8 GUIDE PLATES SBC 5/16"PUSHROD

PRO-66789 PUSH ROD CHECKER

CCA-K12-677-4 CAM KIT

[Mike C]

I have the Comp Magnum 280 mechanical street roller in my 355. The 282s compares favorably, especially with the 1.6 rockers. (My cam is 236 at .050 and .540 gross lift. I lash at .020.) A lot just depends on your heads. Most likely the double humps don't gain a whole lot with lift over .050. As noted above, too radical takes the fun out of it. Stick with the 282s. Many of the older cams don't suffer the failures of the faster ramp profiles of the newer cams. Compare .050 numbers and not advertised numbers. You can fine tune it with the rockers, trying any combination of 1.5/1.6 (all 1.5's, all 1.6's or intake vs. exhaust) to fine tune the cam size. The 282s would like being shifted at 6500 in a 355. Add a couple of hundred revs for a 327.

 

My motor was in a '79 Z/28 with a 292h and an LT-1 intake and it ran 13.70's. The cam swap and Viftor Jr. put it in the 13 teens in my '69. Cold air and underdriven crank pulley dropped it to 12.7. Both cars were virtually same weight with 4.10 gears and Super T10 4 speeds. Best mph with the 292 was 101. With the 280r it's 110.

 

I'm contemplating swap to a Performer RPM and would suggest same intake for your car based on the 2500-6500 rpm powerband.

 

Oh, and my car flat LOVES the double pumper, I'm not a fan of the vac sec carbs, YMMV. I have a Barry Grant 750s3 that flows 1040 cfm (pre-demon carbs). No real mile per hour gain over a Holley 750, but the 4 corner idle is much smoother as well as the midrange.

[pshepard327ci]

Thanks for all the suggestions and help. I decided to go with the XS274 kit from comp cams. Also went with the Pro Magnum roller rockers.

 

Had one more question regarding assembling the valvetrain and such, should i be worried about installing cam and everything several months before i will be able to fire it up. I will use the correct cam assembly lube and i used a heavy weight oil on piston rings. Also have been using royal purple assembly lube for everything else. If i plan on following the correct oil prime and break-in procedures will i be ok installing the cam now and wrapping the engine up until im ready for it? Thanks for your help!

[Pyro]

Should be ok sitting there for a few months.

 

Make sure to use EOS oil additive during the cam break in. And I would use a little EOS at each oil change.

 

I would also consider using just the outer springs for the cam break in. I know it is a main pain to swap springs on an engine but worth it if it saves the cam lobes.

[STROKERACE]

Why don't you try a set of vortec heads with your combo. The vortecs flow alot better than the fuelies. Also a 650 double pumper with machanical secondaries might work out better than the 750. You'll get much crisper throttle response with the 650 than you will with the 750.

[pshepard327ci]

In regards to the Vortec heads, i decided to go with the 462's about 5 years ago and did some port and polishing on them and also had my machine shop touch them up and do the studs and pushrod elongating and valve seats. I probably good have used that money and gone out and got a set of real nice AFR's but this is what i have and it leaves room for a "seat of my pants" improvement down the road. I was thinking 650 or 700 for the carb. I haven't gotten to that point yet.

 

I am installing the cam and heads tomorrow and i will do as Pyro suggested and just install the outer spring for break-in. Do i remove the inner as well as the dampener(i think thats the other part between the inner and outer is?) and just install the outer spring?

[Pyro]

Keep the dampener in place. So use the outer spring and dampener.

 

Do you know what spring pressure you are using? seat and at 0.500" lift?

[pshepard327ci]

Keep the dampener in place. So use the outer spring and dampener.

 

Do you know what spring pressure you are using? seat and at 0.500" lift?

 

Comp Cams #249-986-16

 

# Dual Valve SpringsOuter inside diameter: 1.070"

# Inner inside diameter: .697"

# Seat load: 132lbs @1.750''

# Open load: 293lbs @1.250''

# Coil bind: 1.150''

# Rate: 322lbs/in

# With damper

# 16 per package

 

I think i messed up on getting these with kit or i didnt get all the work needed done on these heads. The springs are larger than the seats on the heads. How much of an expense is that to get machined or should i look at getting a smaller diameter spring. I imagine i need the size comp cams suggests and sent me but im praying its not a several hundred dollar job.

[Pyro]

Ah, go back and read the second post!

 

It isn't that hard or expensive to machine in bigger spring cups. I'm guessing 100.00 should do it, if you disassemble and reassemble yourself.

 

You really should measure your "actual" installed height. This can vary from head to head by a lot. And especially if you re-machine the spring cups.

 

132 on the seat and 293 at 0.050" seems a little high for a flat tappet. I feel compcam tends to use too much spring pressure. 110 to 120 on the seat and 275 at 0.500" should be enough.

[Jerminator96]

I imagine i need the size comp cams suggests and sent me but im praying its not a several hundred dollar job.

 

Well that is the downside to using those old heads, but the machinist is probably only going to charge you for 3 hours of work. Maybe more or less depending on how well you know him. Seeing as how he already worked the heads over for you maybe he'll cut you a deal.I think you should take it as a sign that you are supposed to get some 12* Brodix heads.

[pshepard327ci]

Well i think he gave me a pretty good deal, $80 out the door. He is going to check the height and install them for me (just the outer spring). He replied to that with "man you have been doing some research!"

 

Thanks again and will definitely snap some pics along the way.

[pparaska]

I fully agree with your choice of the cam (XS274) - I ran that cam with 461 pocket ported heads in my 327 (9.7:1) and it was streetable - but more would have been too much. To me, the old Magnum grinds are too slow for what you get. I never had a problem with very comparable springs too. You need a bit of spring with the Xtreme cams, especially if you are going to rev it. I think 7K will be the limit, and you need to make sure your oiling and valvetrain are very good.

 

Personally, I'd go for a 6" rod or more and a piston to work with those - the 5.7" rod 327 pistons are long and heavy - not what you want for a high revving engine!

 

Definitely research the issue of zinc in the oil. EOS or Comp Cam's additive is a great idea, or some of the racing oils that have enough zinc in them. It's another reason to do a roller (next time ).

 

A 650 double pumper carb will be SO MUCH better with this setup. I had a 750 vac sec on my 327 and went to the 650 DP and the difference was incredible. The only vehicle I'd put a vac sec carb on would be a big heavy car or truck. All a vac sec carb does is replace your brain - you're smart enough not to dump all 4 barrels opened at 1500 rpm, so you don't need a vac sec carb. The hit you get from that extra pump is too much fun to give up!!!