Bill, The Largest carb. that I would use on a 327 is a Holley 600 or a Quadrajet 750. You want to have smaller primaries for the street. I would look at the Comp Cams 30-30 nostalgic plus for a camshaft.

 

Imho, since SY1 didn't chime about the -140 cam being ran in a lower compressioned, smaller, SB, I would install a good old CC 270S for grunt or their 282S for more topend in a 10 to 1 CR. 327. (Or onna UDHarold's SOTA cams!!)....

And fwiw, I have a PAW, supposed, 264(I think really a 280)/246, 108/108, .498" gross lift solid lifter cam that need's .030" lash on both sides that cost me $44.95 + S&H for my next junk301!!

pdq67

 

As from personal experience I would say no larger than a cc280 and a 650 carb.

 

Bill I have used it in 12 and 12.5:1 motors only, as has my brother in his 302 cars. I know many people have slipped them into their stock 11:1 302 and spoken up on this board as being happy with them. GM recommends a minimum of 12:1 at least partially because of the late closing intake valve bleeding off so much cylinder pressure. I have run one with a 780 in a 331, but it was 12.5:1. That being said here's what I came up with using your list of components and making a few assumptions of my own on your machining, (that's where I'll probably get into trouble making assumptions)

I assume you are using stock length 5.7 rods and a composite head gasket rather than the old factory steel shim gasket. Also assumed that you didn't deck the block so your piston is still .025" in the hole. If this is all true your gasket is probably .041-.038 thick compressed. With a flat top that'll take you down from 10.25:1 to 9.7:1 with just the thicker head gasket. I considered your .030 bore in this or it would've been a little less yet. Using the 140 cam your dynamic compression would be only 7:1. That's pretty low IMO. You could deck the block to zero or you could run a .015 thick gasket and mill the 64cc heads to 60cc. Those two things alone will up you to 10.9:1 static compression and puts your dynamic compression at 8.1 which is close to the 8.3 or 8.4 that I keep hearing bounced around as the max safe for pump gas without detonation (if someone else has a different figure than this I'd like to hear it because I'm basing my current build on this). Flat milling your heads .006" will reduce your chamber size roughly 1cc, so .024" flat milled would get you into a 60cc chamber. You can flat mill approximately .030" before you need to start worrying about cutting the intake manifold as well, so 60cc would be a good number to shoot for. On I'd do is cc the heads to know for sure the chamber size. Most GM 64 cc heads are actually 65 or 66 by the time they unshroud the chamber for the larger 2.02 intake valves. I don't know what they do with the Bowtie head, but I'd assume they cut the intake side of the chamber like their production heads to allow the larger valve to flow.

Your 034 Bowtie heads are the phase 2 variety and I think the 180 intake ports would be perfect for a street driven 331. I ran ports as small as 171 on a 355 12.5:1 recently and while I gave up much on the top end the 355 was the most responsive street 350 I've ever driven. I'm certain the small ports kept the velocity up, which is really more important to me on a street car than some of the huge ports that guys try to run on the street simply because they work well on drag cars and then complain about the motor being unresponsive down low. I think your heads are a good match for what you are building. The exhaust ports are a little small at 55cc, but then you aren't building a 434 sbc either. Bowtie heads for the most part use the small 55cc exhausts.

Your carb isn't that far off because if you are going solid flat tappet and the short 3.25 stroke the motor should easily go to 7500 rpm. Using CFM= (Cubes x max rpm)/3456 x volumetric efficiency (I'm again assuming and using the high end for a street car with hi-perf parts which typically are 85-95%, so I'm going with 95 so we don't figure too little carb) I come up with 682cfm. To spin it to 8000 rpm you are looking at 728cfm. If you plan on running it to only 7000, which is the high end of the recommended rpm range for the 140 cam, it will rev higher, but starts dropping off above 7000, then 636cfm and the 650 double pumper starts looking just right like AJ suggested.

I'm using the 140 with 1.6 rockers in my destroked 377 by the way. Since it requires 746 cfm to rev to 7200 I'm planning on an annular 750 or 830 double pumper. I'm still a ways off as I just got the block out of machine shop prison this week.

Bottom line is I think you'll want more compression with that cam and maybe a little less carb, but not too much less. I think your heads are a good fit. Don't up the compression with domed pistons, your flat tops are the only way to go. Play with milling the heads and gasket thickness and I think you can get close to the 11:1 figure that others have run the cam with. Remember though as you mill the heads the valves get close to the piston, so mock up you combo and clay the valve to piston clearance first to see how much clearance you have with 1.5 rockers. You want a minimum of .100" I wouldn't go any closer than .080" by any means.

Bill I have one book here that lists your heads as 190 cc intake ports, others say 180. I don't know which to go by. If it means anything the book that lists them at 190 also has the wrong lift numbers for the 140 cam, so they are wrong at least on the cam.

Good luck on your build. It's all about matching components and I just think you'll want a little more compression with that cam, especially with a short stroke motor.

 

Question for SY1

Bill I have used it in 12 and 12.5:1 motors only, as has my brother in his 302 cars. I know many people have slipped them into their stock 11:1 302 and spoken up on this board as being happy with them. GM recommends a minimum of 12:1 at least partially because of the late closing intake valve bleeding off so much cylinder pressure. I have run one with a 780 in a 331, but it was 12.5:1. That being said here's what I came up with using your list of components and making a few assumptions of my own on your machining, (that's where I'll probably get into trouble making assumptions)

I assume you are using stock length 5.7 rods and a composite head gasket rather than the old factory steel shim gasket. Also assumed that you didn't deck the block so your piston is still .025" in the hole. If this is all true your gasket is probably .041-.038 thick compressed. With a flat top that'll take you down from 10.25:1 to 9.7:1 with just the thicker head gasket. I considered your .030 bore in this or it would've been a little less yet. Using the 140 cam your dynamic compression would be only 7:1. That's pretty low IMO. You could deck the block to zero or you could run a .015 thick gasket and mill the 64cc heads to 60cc. Those two things alone will up you to 10.9:1 static compression and puts your dynamic compression at 8.1 which is close to the 8.3 or 8.4 that I keep hearing bounced around as the max safe for pump gas without detonation (if someone else has a different figure than this I'd like to hear it because I'm basing my current build on this). Flat milling your heads .006" will reduce your chamber size roughly 1cc, so .024" flat milled would get you into a 60cc chamber. You can flat mill approximately .030" before you need to start worrying about cutting the intake manifold as well, so 60cc would be a good number to shoot for. On I'd do is cc the heads to know for sure the chamber size. Most GM 64 cc heads are actually 65 or 66 by the time they unshroud the chamber for the larger 2.02 intake valves. I don't know what they do with the Bowtie head, but I'd assume they cut the intake side of the chamber like their production heads to allow the larger valve to flow.

Your 034 Bowtie heads are the phase 2 variety and I think the 180 intake ports would be perfect for a street driven 331. I ran ports as small as 171 on a 355 12.5:1 recently and while I gave up much on the top end the 355 was the most responsive street 350 I've ever driven. I'm certain the small ports kept the velocity up, which is really more important to me on a street car than some of the huge ports that guys try to run on the street simply because they work well on drag cars and then complain about the motor being unresponsive down low. I think your heads are a good match for what you are building. The exhaust ports are a little small at 55cc, but then you aren't building a 434 sbc either. Bowtie heads for the most part use the small 55cc exhausts.

Your carb isn't that far off because if you are going solid flat tappet and the short 3.25 stroke the motor should easily go to 7500 rpm. Using CFM= (Cubes x max rpm)/3456 x volumetric efficiency (I'm again assuming and using the high end for a street car with hi-perf parts which typically are 85-95%, so I'm going with 95 so we don't figure too little carb) I come up with 682cfm. To spin it to 8000 rpm you are looking at 728cfm. If you plan on running it to only 7000, which is the high end of the recommended rpm range for the 140 cam, it will rev higher, but starts dropping off above 7000, then 636cfm and the 650 double pumper starts looking just right like AJ suggested.

I'm using the 140 with 1.6 rockers in my destroked 377 by the way. Since it requires 746 cfm to rev to 7200 I'm planning on an annular 750 or 830 double pumper. I'm still a ways off as I just got the block out of machine shop prison this week.

Bottom line is I think you'll want more compression with that cam and maybe a little less carb, but not too much less. I think your heads are a good fit. Don't up the compression with domed pistons, your flat tops are the only way to go. Play with milling the heads and gasket thickness and I think you can get close to the 11:1 figure that others have run the cam with. Remember though as you mill the heads the valves get close to the piston, so mock up you combo and clay the valve to piston clearance first to see how much clearance you have with 1.5 rockers. You want a minimum of .100" I wouldn't go any closer than .080" by any means.

Bill I have one book here that lists your heads as 190 cc intake ports, others say 180. I don't know which to go by. If it means anything the book that lists them at 190 also has the wrong lift numbers for the 140 cam, so they are wrong at least on the cam.

Good luck on your build. It's all about matching components and I just think you'll want a little more compression with that cam, especially with a short stroke motor.

I have a similar build that I am doing, 327. I have some forged Speed Pro's flattops .040 with 4 reliefs. I am running casting 492 heads with 2.02 valves. Compression will hit around 10 to 1? 492's are listed at 64CC's. I may have them check the cc's. I am thinking about running a 280H or equivalent cam. I will probably run the 650 DP MS also. Running a 4 speed and 3.55 or 3.73's..... Opinion?

 

SY1, thank you very much for the very detailed write up. Your assumptions were all right on the mark. I will be using 5.7 rods, a non decked block w/ TRW flat tops with 4 valve reliefs. I will be using a .015" shim head gasket and not a composite gasket, this will help somewhat with the compression. The 034's are advertised at 62 cc chamber volume, they have not been machined in anyway. In fact, they are brand new. They have been in my basement for years and never bolted on an engine.

I am still tempted to try the 140 cam anyway. What could be the worst that can happen, a rough idle and a pig to drive? My mind is very open to the opinions of people that know far more about this than I do. However, I do have several other cams in my spare parts stash. I have another new GM cam, the old 375HP #346. I have run this cam happily in a 327 10.5 compression engine. I also have a Comp cam 294S and a Comp Cam 292H. I guess I really want the mechanical sound the solids will provide. The engine is being assembled for a Vega project. I drive the car regularly with its 262 V-8. Truthfully, I am bored with this very docile engine even though it has a few hop up parts that were installed by the cars builder. The car has a 4 speed and is so much fun to drive on the street. The rear tires are only 24" in diameter with 5 lugs. I am uncertain of the gearing in my Saginaw, the previous owner thought it was a 3.50 first gear. My rear gears are in the low 3's. I do not want a cam that will give me gobbs of low end torque, I know the 140 cam is very weak at low RPM. This car is not one that will be power shifted and abused regularly. I know when this cam comes on you had better hold on, you are in for a fast ride!

I appreciate your very honest and technical analysis of what Iam building. Originally the car was going to have a 355, I changed my mind because I like the sound of the high reving short stroke 327. I am also very concerned about the over heating problems other people have encounter ed with the bigger engine in a Vega. The 65 Impala I bought new had a 300 horse 327, that was a great engine even in that heavy 4000 pound car. The Vega is almost half the weight of that car with a potentially more powerful engine. This will be a scary ride as it is, and will take some care to drive safely.


I was pleased to hear you agreed with most of my combo. I will also be using 1.52 Comp roller rockers. My car has power brakes so I will be using a secondary vacuum canister to help with my weak vacuum. One of my friends has a built 69 L-88 Chevelle. He runs the canister on his car with great success on the PB. His car is wicked with the stock GM L-88 cam.

Now that you know my thoughts and the car I am building, please give me more of your honest thoughts.
Bill

 

Degree it 2 advanced with that cam.

Youll like it I think. Course, Im no mech/engine builder either. all IMHO

 

Bill,

I'm glad Dave popped in.

Bill,

I will say this, that no more than a stock, 300hp/327 with just bowl-blended heads, a tuned, 750 cfm 3310- Holley 4-barrel carb on a their old 300-36, true high-rise dual plane, and a set of cheap, 4-tube, long headers and an open exhaust and this CHEAP PAW solid lifter cam WILL COOK!!

PAW call's it their 264/246 in my cat, BUT I figure it is really PAW's copy of this reboxed Elgin jobber!!

E-1133-P; 280/246, 108/106, .498”, Lash, .030” and .030”..

It's going in my next junk292/301 depending on piston costs. I'm going to shift it at 8,000 rpm just for the fun of it!! Sucker is in my bedroom closet now!

pdq67

 

Youll get the same answers as Bill, Joe. lets see what others think....

 

I like about .480 lift for street. But, I always run a 4 speed. If you are running an auto and 3.08's, then you might be looking at the 268h or a 327 350 horse type of cam. Just my opinion. If it doesnt work add more gears!

 

Anything less than 11:1 with the 30-30 is a waste. It would bet that it would at least be the same with the #140 cam. RamAirDave, what was the SCR in the 302s you used the #140 in?

 

Bill your gears will act like much larger numerical gears with that low first gear and the short 24" tires. I think that'll help out a bunch with the soft bottom end you'll likely encounter with the 140. Harley had what I think is a good idea in advancing the cam 2 degrees. I know advancing it 4 degrees will close the intake early enough to net you another .3 of dynamic compression and move the power range down as much as 400 rpm. Both of those would make the 140 more street friendly. I don't know how GM calculates their timing events, some manufacturers build in 4 degrees of advance into their grinds, if this is the case you won't want to install it advanced. Actually GM doesn't grind this any longer, but gets their GM Performance Parts 140 cam they offer today from Crane. Clevite also still offers the grind today and that's the one I'm using in the 377 sbc going together right now.

You are wise to use the vacum canister because the vacum is quite low on the 140. On my 12.5:1 331 I only had 6.5-7 " of vacum at idle, so low that the power valve was opening on my Holley until I installed a 4.5 PV. The canister should help you.

I had a 262 in a 75 Nova, I understand wanting to move up. At 110 hp the little motor can't get out of it's own way. The 3.10 stroke some have suggested may be good to use in a larger bore block, but it's still a cast crank. I blew several TH350 transmissions, a torque converter and the rear end out of the Nova, but the little 263/110hp motor never suffered any problems no matter how hard I drove it. So it'll take a lot of abuse, but it's not putting out much power or torque either.

Joe's build is very similar, but IMO the iron heads are going to limit him compression wise. The aluminum head will allow you to run an additional point of compression. Joe like I told Bill I don't know how the 140 will act on anything less than 12:1, but I know guys run it on 11:1 motors. I don't know if 10:1 is going to work well, but I wouldn't expect it to work real well because the DCR starts getting so low, like 7:1. There are a lot of good cams out there that'll work better than the 140 at 10:1 and pdq can probably jump in here with some suggestions.

 

I just mentioned the one I have for my next junk301 as well as any of the 268 up to 276 or so cams.

The old OBSOLETE stock, Duntov is a dandy! Add 1.6 ratio rockers.

pdq67

 

PDQ67, are you referring to the 097 cam or the 346 cam? Today both of these cams are definitely obsolete. I have decided NOT to run the 140 cam based on the opinions of everyone here. If I were running the higher compression and racing the car it would be a good competitive cam.

You mentioned the Elgin #1133 cam, how will this fit my application? This is actually the GM #346 replacement that I already have. What about their cam #1131? Is this a single pattern cam?

I did use the Elgin 920 cam you suggested for my 355, this is the engine I was planning to use in the Vega, I will enjoy the 331 more and not have to worry about the overheating issues during the hot summer days.

Thanks to all.
Bill

 

Bill,

The Duntov is the early cam and is spec'd at;

287/228/287/230, 110.5/108, and like .385" lift on both sides when lashed at .012" and .018".

The -346 or 30-30/fuelie cam is spec'd;

346/314/304/254, 114/112, .485" gross lift and need's .030" lash on both sides.

I say, 346 per GM, 314 per W/B/R and finally 304 per Pat Kelley so take your pick, I use 314..