Improving Stock Cylinder Head Performance - The 1947 - Present Chevrolet & GMC Truck Message Board Network

LT-102 · 01-08-2003, 10:55 PM

What can I do to my stock #487X heads to increase their performance? It's a 1971, 350 that has been rebuilt with a less than satisfactory cam. The heads were redone at the same time, but not with any special performance enhancements. I'm planning on kicking up the perfomance and going to Comp Cams camshaft with 224/230 duration, 477/480 lift and 110 lobe separation. 750 carb. Compression is about 9.4 to 1.

What can I have a machine shop do to the heads to better their performance? A best guess on what it would cost would be helpful. Thanks

LT-102 · 01-08-2003, 11:08 PM

One thing I forgot, I may go to 1.6 rockers, and that would make my valve lift, 509/512. Should I get the studs changed from pressed in to screwed in?

mikep · 01-08-2003, 11:49 PM

Run. Do not walk . To the store or telephone and order yourself up a set of Z28 style valve springs. Make sure they are rated for .550 lift at their installed height. Some are not. Look for around 110 lbs at installed height spring pressure. Dont go over 270lbs or so compressed spring pressure for regular street driving unless you like flat lobes. With stock springs you'll float your valves without really trying very hard at the RPM where that cam is starting to make good power. I can show you some pistons with big dents in them and a few bent valves if you'd like proof.

487's are half decent factory castings. Without getting too far into porting you should be able to pick up a few horses gasket matching the intake ports and polishing up the bowl areas.

minibike · 01-08-2003, 11:57 PM

the vortec heads are better flowing than many aftermarket heads, but you would have to get a different intake to match the ports.

Durney · 01-09-2003, 12:00 AM

I have puposely not given advise here because of the last attitude given by a few on this board but what the hey...many here have helped me recently.

This is a very BIG question you asked.....

Do NOT take them to joe machine shop and let them "port" your heads. Find someone who specializes in professional head work if you expect to see any decent results. You can tell a pro by the following:

He will have a Serdi, he will have a flow bench, he will have LOTS of experience and references, and he will have a wait.

He will also have higher prices than joe machine shop but if you havent figured out yet in this world you get what you pay for.

There is little to no flow improvement by opening the port "window" unless there is an obvious mismatch and then manifold work should be the choice.

Most "porters" WILL do more damage than good. PERIOD. You can clean out the bowls youself but even this will not help without a valve job MATCHED to your useage.

good luck

bigjimzlll · 01-09-2003, 12:08 AM

a little bowl port work...multi-angle valve job..back cut the valves..go with screw in studs..elongate the pushrod holes(if you insist on using 1.6 rockers) you will see very little improvement with gasket matching(IMHO) Using 1.6 rockers is not a magic bullet, some engines will see some improvement...some will see a decrease in performance..if you are trying to crutch a cam..Get the right cam..if your fine tuning on a dyno..give it a shot...I just dont think its worth the stress it puts on the valve train.
Jim

jiggs · 01-09-2003, 12:35 AM

http://www.sa-motorsports.com/diyport.htm --- a good reference for cleaning up your heads. What they are doing is a street/strip port job that would usually cost about $500. There is no black magic as far as cleaning up a head, just don't go hog wild about removing metal. If you just blend the shortcomings of what the factory did, you will see improvement.

RON WOODGEARD · 01-09-2003, 12:41 AM

Durney's right.....So's BigJim.........

Unless you take the heads to a knowledgable PRO, it can Permanently hurt the heads instead of improving them.

Depending on what your after, I would just go to the cam you mentioned. Don't screw with 1.6 rockers, If you want more cam then go more cam. Screw in studs never hurt, but i've ran equivalent to that cam with no problems.
Yes, A little stiffer is good also, but you didn't mention if they gave you new ones when you had what work done to them you had. If they're new they "should"be up to par. That cam if i remember right is rated 17,1800 RPM,to 6000 RPM. And realistically, how many times are you going to rev it that high. And if you are really concerned about the springs, then buy the complete kit. (Cam,springs,and lifters) Then you know it's "matched"

Good luck, let us know what you decide and how it goes.

RON

mikep · 01-09-2003, 01:20 AM

6000 RPM is nothing. I have a smaller cam than that and I regularly hit 6500 RPM . Regularly as in every day 7 or 8 times at least. Manual transmission driving is a lot different than slushbox driving. Get the springs if you drive hard. If you dont then there is no point in getting that cam.

OK we are talking street driving with a 350 here .... As far as taking the heads to a porter ....It is a total waste of money. Any decent porter will charge you WAY more to port and test your heads than you will pay for good flowing aftermarket jobs that flow better out of the box than you could ever possibly get out of those 487X heads. In my eyes the best bang for the buck on the street are the Pro lightning 200 CC heads. Theyre modeled after Vortecs but with improved exhaust ports and larger valves and port cross sections. For $750 a set you cant beat it. $750 worth of porting will get you a bowl cleanup and head rebuild on your 487's and flow NO WHERE NEAR the numbers the pro lighnings will give. And unlike the Vortecs they do not require special intake manifolds or valve train accesories. I picked up a set for a motor I'm building my brother the other day and the castings are so good I'll be ordering up a set for myself next month when my 4th qtr bonus check comes in.

As far as the 1.6 rockers. Theyre not a crutch.Check out the cam lobe specs on just about every manufactureres lobes. One lobe gets used on multiple different engines . The small block chevy has one of the lowest available ratios . That doesnt help anything. Fords use the same lobes with a 1.6 in their small blocks. Some small block engines such as the 351 Cleveland go as high as 1.72 in ratio with the exact same spec lobes. If your heads flow good in the .500" range then it benefits you to get the valve there quickly an keep it there as long as possible .

Anyone want a slightly used set of World product SR Torquers?

bigjimzlll · 01-09-2003, 01:28 AM

how much Mike

mikep · 01-09-2003, 01:38 AM

Theyr'e the older style with the screw in studs and stepped guide plates that can be used with 1.6 rockers, .550" lift springs , 170 CC intake ports , 76 CC chambers . Just passed 5000 miles on the heads since I installed them on this motor and they were new in the box before that. I'd take $375 plus shipping.

neonlarry · 01-09-2003, 02:00 AM

I'm looking for some heads too, if you want to sell the torquers I wight be interested. Also, where did you get the other heads from that you were talking about? I haven't really looked for them, but I have never seen or heard of them before either.

bigjimzlll · 01-09-2003, 07:55 AM

thats a good deal Mike..I would want the 67cc ones..someone will get a good deal though.
Jim

mikep · 01-09-2003, 08:16 AM

http://proshaver.com/netspecial.htm

http://proshaver.com/ProCatalog.pdf

Theres several distributors of the pro action heads but heres one with pretty good pricing. I got the 200 cc angle plugs for my brother and will probably for myself too.

My WP's I'll be putting up for sale end of next month or so. Theyre good heads in their own right and are probably the most streetable performance head going but I have one little problem....I drive like an idiot!

neonlarry · 01-09-2003, 12:29 PM

I have been thinking about buying a set of the torquers anyway, so put me first in line when you are ready to sell them. I am definintly interested in them. (unless I can come up with enough money to buy a set of the other ones. lol)

Mike C · 01-09-2003, 03:15 PM

If you really want to know how to wake up your GM heads, go to www.motorbooks.com and look for David Vizard's book "How to Build and Modify Small Block Chevy Cylinder Heads" it is very well done and will allow you to mod your own heads for flow in the 240 cfm range, 260 if you are good. (As comparison, my CNC Heads ported LT1 flow 267 cfm , all flow figures referenced at .500 lift) Cylinder head porting is a little more involved than just getting advice on a message board, but it is a good place to start.

01-08-2003, 10:55 PM	#1
LT-102 Registered User Join Date: Nov 2000 Location: Greenville, Oh USA Posts: 166	Improving Stock Cylinder Head Performance What can I do to my stock #487X heads to increase their performance? It's a 1971, 350 that has been rebuilt with a less than satisfactory cam. The heads were redone at the same time, but not with any special performance enhancements. I'm planning on kicking up the perfomance and going to Comp Cams camshaft with 224/230 duration, 477/480 lift and 110 lobe separation. 750 carb. Compression is about 9.4 to 1. What can I have a machine shop do to the heads to better their performance? A best guess on what it would cost would be helpful. Thanks

01-08-2003, 11:49 PM	#3
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Run. Do not walk . To the store or telephone and order yourself up a set of Z28 style valve springs. Make sure they are rated for .550 lift at their installed height. Some are not. Look for around 110 lbs at installed height spring pressure. Dont go over 270lbs or so compressed spring pressure for regular street driving unless you like flat lobes. With stock springs you'll float your valves without really trying very hard at the RPM where that cam is starting to make good power. I can show you some pistons with big dents in them and a few bent valves if you'd like proof. 487's are half decent factory castings. Without getting too far into porting you should be able to pick up a few horses gasket matching the intake ports and polishing up the bowl areas. __________________ No truck :-(

01-09-2003, 12:08 AM	#6
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	a little bowl port work...multi-angle valve job..back cut the valves..go with screw in studs..elongate the pushrod holes(if you insist on using 1.6 rockers) you will see very little improvement with gasket matching(IMHO) Using 1.6 rockers is not a magic bullet, some engines will see some improvement...some will see a decrease in performance..if you are trying to crutch a cam..Get the right cam..if your fine tuning on a dyno..give it a shot...I just dont think its worth the stress it puts on the valve train. Jim __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

01-09-2003, 12:35 AM	#7
jiggs poker face Join Date: Jul 2002 Location: Saskatoon, Saskatchewan Posts: 218	http://www.sa-motorsports.com/diyport.htm --- a good reference for cleaning up your heads. What they are doing is a street/strip port job that would usually cost about $500. There is no black magic as far as cleaning up a head, just don't go hog wild about removing metal. If you just blend the shortcomings of what the factory did, you will see improvement. __________________ If you could kick the person in the *ss responsible for most of your trouble, you wouldn't sit for a month.

01-09-2003, 01:20 AM	#9
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	6000 RPM is nothing. I have a smaller cam than that and I regularly hit 6500 RPM . Regularly as in every day 7 or 8 times at least. Manual transmission driving is a lot different than slushbox driving. Get the springs if you drive hard. If you dont then there is no point in getting that cam. OK we are talking street driving with a 350 here .... As far as taking the heads to a porter ....It is a total waste of money. Any decent porter will charge you WAY more to port and test your heads than you will pay for good flowing aftermarket jobs that flow better out of the box than you could ever possibly get out of those 487X heads. In my eyes the best bang for the buck on the street are the Pro lightning 200 CC heads. Theyre modeled after Vortecs but with improved exhaust ports and larger valves and port cross sections. For $750 a set you cant beat it. $750 worth of porting will get you a bowl cleanup and head rebuild on your 487's and flow NO WHERE NEAR the numbers the pro lighnings will give. And unlike the Vortecs they do not require special intake manifolds or valve train accesories. I picked up a set for a motor I'm building my brother the other day and the castings are so good I'll be ordering up a set for myself next month when my 4th qtr bonus check comes in. As far as the 1.6 rockers. Theyre not a crutch.Check out the cam lobe specs on just about every manufactureres lobes. One lobe gets used on multiple different engines . The small block chevy has one of the lowest available ratios . That doesnt help anything. Fords use the same lobes with a 1.6 in their small blocks. Some small block engines such as the 351 Cleveland go as high as 1.72 in ratio with the exact same spec lobes. If your heads flow good in the .500" range then it benefits you to get the valve there quickly an keep it there as long as possible . Anyone want a slightly used set of World product SR Torquers? __________________ No truck :-(

01-08-2003, 11:08 PM	#2
LT-102 Registered User Join Date: Nov 2000 Location: Greenville, Oh USA Posts: 166	One thing I forgot, I may go to 1.6 rockers, and that would make my valve lift, 509/512. Should I get the studs changed from pressed in to screwed in?

01-08-2003, 11:57 PM	#4
minibike Registered User Join Date: Jun 2002 Location: Lafayette, LA Posts: 500	the vortec heads are better flowing than many aftermarket heads, but you would have to get a different intake to match the ports. __________________ 69 SWB LT1/4L60E www.classicplace.com

01-09-2003, 12:00 AM	#5
Durney Registered User Join Date: Jul 2002 Location: Michigan Posts: 158	I have puposely not given advise here because of the last attitude given by a few on this board but what the hey...many here have helped me recently. This is a very BIG question you asked..... Do NOT take them to joe machine shop and let them "port" your heads. Find someone who specializes in professional head work if you expect to see any decent results. You can tell a pro by the following: He will have a Serdi, he will have a flow bench, he will have LOTS of experience and references, and he will have a wait. He will also have higher prices than joe machine shop but if you havent figured out yet in this world you get what you pay for. There is little to no flow improvement by opening the port "window" unless there is an obvious mismatch and then manifold work should be the choice. Most "porters" WILL do more damage than good. PERIOD. You can clean out the bowls youself but even this will not help without a valve job MATCHED to your useage. good luck

01-09-2003, 12:41 AM	#8
RON WOODGEARD Resident Young Old Dude ! Join Date: Jul 2001 Location: Nevada Posts: 1,948	Durney's right.....So's BigJim......... Unless you take the heads to a knowledgable PRO, it can Permanently hurt the heads instead of improving them. Depending on what your after, I would just go to the cam you mentioned. Don't screw with 1.6 rockers, If you want more cam then go more cam. Screw in studs never hurt, but i've ran equivalent to that cam with no problems. Yes, A little stiffer is good also, but you didn't mention if they gave you new ones when you had what work done to them you had. If they're new they "should"be up to par. That cam if i remember right is rated 17,1800 RPM,to 6000 RPM. And realistically, how many times are you going to rev it that high. And if you are really concerned about the springs, then buy the complete kit. (Cam,springs,and lifters) Then you know it's "matched" Good luck, let us know what you decide and how it goes. RON

01-09-2003, 01:28 AM	#10
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	how much Mike __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

01-09-2003, 01:38 AM	#11
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Theyr'e the older style with the screw in studs and stepped guide plates that can be used with 1.6 rockers, .550" lift springs , 170 CC intake ports , 76 CC chambers . Just passed 5000 miles on the heads since I installed them on this motor and they were new in the box before that. I'd take $375 plus shipping. __________________ No truck :-(

01-09-2003, 02:00 AM	#12
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,745	I'm looking for some heads too, if you want to sell the torquers I wight be interested. Also, where did you get the other heads from that you were talking about? I haven't really looked for them, but I have never seen or heard of them before either. __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

01-09-2003, 07:55 AM	#13
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	thats a good deal Mike..I would want the 67cc ones..someone will get a good deal though. Jim __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

01-09-2003, 08:16 AM	#14
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	http://proshaver.com/netspecial.htm http://proshaver.com/ProCatalog.pdf Theres several distributors of the pro action heads but heres one with pretty good pricing. I got the 200 cc angle plugs for my brother and will probably for myself too. My WP's I'll be putting up for sale end of next month or so. Theyre good heads in their own right and are probably the most streetable performance head going but I have one little problem....I drive like an idiot! __________________ No truck :-(

01-09-2003, 12:29 PM	#15
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,745	I have been thinking about buying a set of the torquers anyway, so put me first in line when you are ready to sell them. I am definintly interested in them. (unless I can come up with enough money to buy a set of the other ones. lol) __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI



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01-09-2003, 03:15 PM	#16
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	If you really want to know how to wake up your GM heads, go to www.motorbooks.com and look for David Vizard's book "How to Build and Modify Small Block Chevy Cylinder Heads" it is very well done and will allow you to mod your own heads for flow in the 240 cfm range, 260 if you are good. (As comparison, my CNC Heads ported LT1 flow 267 cfm , all flow figures referenced at .500 lift) Cylinder head porting is a little more involved than just getting advice on a message board, but it is a good place to start. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

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