C heads small valve
July 5th, 2009, 08:11 PM
#1
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C heads small valve
I'll be dropping off some small valve C heads this week for a valve job. When it comes to more HP I've made poor decisions in the past. I was wondering what difference the bigger valves would make in a 455 9.5-1 motor with a quadrajet. I feel I don't drive the car enough to worry about hardened seats, but I may be wrong about that too. I'm guessing .010 in the 1/4 mile difference?
Please talk me out of getting the big valves.
Dave
Please talk me out of getting the big valves.
Dave
July 5th, 2009, 09:02 PM
#2
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Location: Medford, Oregon
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Sorry Dave, no help here. Get the BIG valves
I don't have any numbers but it makes sense to me that if the engine breaths better it will be a good thing! In the big picture if your going to go to the expense of rebuilding the heads I don't think it will cost much more to cut them out for the large intake valves. Do you have a cost comparision for the two options? For what it's worth that's my 2 cents! John
I don't have any numbers but it makes sense to me that if the engine breaths better it will be a good thing! In the big picture if your going to go to the expense of rebuilding the heads I don't think it will cost much more to cut them out for the large intake valves. Do you have a cost comparision for the two options? For what it's worth that's my 2 cents! John
July 5th, 2009, 09:18 PM
#3
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Location: Chicago
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My advice is, don't bother unless you're going to drag race on a regular basis.
AND if you do intend on regularly racing, there's more things that should be addressed on old iron heads than a simple valve job.
If you keep the small valves, they're good for another valve job or 2, and once the smaller seats are a little worn, then you can get them cut for bigger valves and start semi fresh again.
You will sink a lot of money into stock heads to make them the best they can be, and there is potential. Personally, I'd rather just buy a set of ebrocks than sinking a grand or 2 into old irons, but then again, I don't personally know any of the olds iron head artists out there.
I have about $400 into a set of milled and ported GA's on my daily driver and they're not particularly fast.
Best thing to have is a horsepower goal or "feel" for the car in mind. Then you can choose the best route to achieve your goal. A lot of your hard earned dollars will be saved this way.
AND if you do intend on regularly racing, there's more things that should be addressed on old iron heads than a simple valve job.
If you keep the small valves, they're good for another valve job or 2, and once the smaller seats are a little worn, then you can get them cut for bigger valves and start semi fresh again.
You will sink a lot of money into stock heads to make them the best they can be, and there is potential. Personally, I'd rather just buy a set of ebrocks than sinking a grand or 2 into old irons, but then again, I don't personally know any of the olds iron head artists out there.
I have about $400 into a set of milled and ported GA's on my daily driver and they're not particularly fast.
Best thing to have is a horsepower goal or "feel" for the car in mind. Then you can choose the best route to achieve your goal. A lot of your hard earned dollars will be saved this way.
Last edited by J-(Chicago); July 5th, 2009 at 09:30 PM.
July 5th, 2009, 09:28 PM
#4
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First thing you need is an honest and fair machinist, that will tell what you can and cannot get away with to achieve your goal instead of just reaching into your pocket.
There are a lot of "Might as wells" that could be done now that your heads are off.
I'd be more worried about the guides than the valve size for the moment.
Figure out the cost of new guides, springs, rockers, bridges, valves, milling (to achieve your desired compression ratio) gaskets, bolts, and valvetrain shims.
"might as well" put in new pushrods to match your fresh top end.
Sit with your machinist and a calculator and watch the money fly right onto the punchlist before you pull the trigger.
AND if and after you do all of those things.... you may not be happy with it if you were expecting 100 more horsepower. Not likely to happen.
There are a lot of "Might as wells" that could be done now that your heads are off.
I'd be more worried about the guides than the valve size for the moment.
Figure out the cost of new guides, springs, rockers, bridges, valves, milling (to achieve your desired compression ratio) gaskets, bolts, and valvetrain shims.
"might as well" put in new pushrods to match your fresh top end.
Sit with your machinist and a calculator and watch the money fly right onto the punchlist before you pull the trigger.
AND if and after you do all of those things.... you may not be happy with it if you were expecting 100 more horsepower. Not likely to happen.
July 5th, 2009, 09:39 PM
#5
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I notice you said your motor is a 9.5-1 so a lot of milling might not be needed for your application, but for everyone else, I'll use this as an example:
Most 71' 455 motors had 40 cc dish in the pistons. Big ol' soup bowl like dish.
If you simply change head gaskets from stock factory to fel-pro, you will be at 7.8-1 compression if you don't have them milled.
I think a good price on milling would be $100 for every .030 shaved off.
If you mill .070 off of the heads and use a fel-pro gasket you'll probably only be around 8.8-1 compression.
Compression is the poor man's ticket to extra ponies.
Then cam, then valve job. If you want your car to be quick on the street.... torque, big tires, and numerically high rearend gears will make you a great stoplight racer that will not be desireable on the expressway.
Most 71' 455 motors had 40 cc dish in the pistons. Big ol' soup bowl like dish.
If you simply change head gaskets from stock factory to fel-pro, you will be at 7.8-1 compression if you don't have them milled.
I think a good price on milling would be $100 for every .030 shaved off.
If you mill .070 off of the heads and use a fel-pro gasket you'll probably only be around 8.8-1 compression.
Compression is the poor man's ticket to extra ponies.
Then cam, then valve job. If you want your car to be quick on the street.... torque, big tires, and numerically high rearend gears will make you a great stoplight racer that will not be desireable on the expressway.
Last edited by J-(Chicago); July 5th, 2009 at 09:49 PM.
July 5th, 2009, 09:41 PM
#6
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Location: Chicago
Posts: 5,468
In short, let us know your goal for the car, and we can be of better help to you and/or your machinist if he doesn't do Oldsmobiles on a regular basis. Oldsmobiles, and horsepower upgrades have been around for a long time. There's no need to have to trial and error your way to the finished product.
Last edited by J-(Chicago); July 5th, 2009 at 09:44 PM.
July 6th, 2009, 06:09 AM
#7
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In short, let us know your goal for the car, and we can be of better help to you and/or your machinist if he doesn't do Oldsmobiles on a regular basis. Oldsmobiles, and horsepower upgrades have been around for a long time. There's no need to have to trial and error your way to the finished product.
July 6th, 2009, 07:33 AM
#8
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X2 on sit down with the machinist.
When I built my 455 with 15 cc dish pistons I wanted the heads to make the most use of the compression, my machinist worked up the cost of the hardened seats enlarging to the bigger valves, new valves, springs, etc. and to my suprise the edelbrock heads complete were only $600.00 dollars more plus they are 77 cc heads so you get the added bonus of higher compression, so I went with the edelbrock and am very happy with the results.
The cost could be lower were you live and you might end up with a better estimate on your original heads then I did.
Your other option is finding a set of large valve C or E heads and go that direction which should be less costly.
Check with 2blue442 he usually has Large valve heads available
Added note: I found a set of edelbrock heads that had never been installed on craigs list for 1600.00 and the guy selling them threw in a new set of roller rockers. I plan on using these heads on the 455 I am building for the 48 Olds. Shop around you never know what you might find.
When I built my 455 with 15 cc dish pistons I wanted the heads to make the most use of the compression, my machinist worked up the cost of the hardened seats enlarging to the bigger valves, new valves, springs, etc. and to my suprise the edelbrock heads complete were only $600.00 dollars more plus they are 77 cc heads so you get the added bonus of higher compression, so I went with the edelbrock and am very happy with the results.
The cost could be lower were you live and you might end up with a better estimate on your original heads then I did.
Your other option is finding a set of large valve C or E heads and go that direction which should be less costly.
Check with 2blue442 he usually has Large valve heads available
Added note: I found a set of edelbrock heads that had never been installed on craigs list for 1600.00 and the guy selling them threw in a new set of roller rockers. I plan on using these heads on the 455 I am building for the 48 Olds. Shop around you never know what you might find.
Last edited by citcapp; July 6th, 2009 at 07:36 AM.
July 6th, 2009, 07:52 AM
#9
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Join Date: Aug 2007
Posts: 2,250
My advice is, don't bother unless you're going to drag race on a regular basis.
AND if you do intend on regularly racing, there's more things that should be addressed on old iron heads than a simple valve job.
If you keep the small valves, they're good for another valve job or 2, and once the smaller seats are a little worn, then you can get them cut for bigger valves and start semi fresh again.
You will sink a lot of money into stock heads to make them the best they can be, and there is potential. Personally, I'd rather just buy a set of ebrocks than sinking a grand or 2 into old irons, but then again, I don't personally know any of the olds iron head artists out there.
I have about $400 into a set of milled and ported GA's on my daily driver and they're not particularly fast.
Best thing to have is a horsepower goal or "feel" for the car in mind. Then you can choose the best route to achieve your goal. A lot of your hard earned dollars will be saved this way.
AND if you do intend on regularly racing, there's more things that should be addressed on old iron heads than a simple valve job.
If you keep the small valves, they're good for another valve job or 2, and once the smaller seats are a little worn, then you can get them cut for bigger valves and start semi fresh again.
You will sink a lot of money into stock heads to make them the best they can be, and there is potential. Personally, I'd rather just buy a set of ebrocks than sinking a grand or 2 into old irons, but then again, I don't personally know any of the olds iron head artists out there.
I have about $400 into a set of milled and ported GA's on my daily driver and they're not particularly fast.
Best thing to have is a horsepower goal or "feel" for the car in mind. Then you can choose the best route to achieve your goal. A lot of your hard earned dollars will be saved this way.
July 6th, 2009, 09:10 AM
#10
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Join Date: Dec 2008
Location: Somerset Wisconsin
Posts: 1,167
I just pulled a valve out of the C head and needed a hammer to get it out.
It looks like several of the valves are junk, and a cheap job is out of the question. I like the idea with the Edelbrock heads. It makes sense to me. I need to have a garage sale and round up some money.
Thanks for the help guys.
Dave
It looks like several of the valves are junk, and a cheap job is out of the question. I like the idea with the Edelbrock heads. It makes sense to me. I need to have a garage sale and round up some money.
Thanks for the help guys.
Dave
July 6th, 2009, 04:44 PM
#11
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Location: Phx, AZ
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Rbuild the C heads, and get some 2.072 valves.
Talk to your machinist about prices.
If he is that expensive, then go Edelbrock.
Remember, Edelbrocks will require some extra's too.
Rockers, pushrods, head bolts will add onto the price, and they still do not flow any better than stockers, until they get ported.
If you can not get the C heads bolted on with 2.072's in them for under $750, you should find another machinist.
That is a far cry from the near $2K to get the Edelbrocks running.
A 2.00 inch valved head usually flows around 205 max on the intake side of a BBO head, and the 2.072 will get you around 240-250 cfm if done correctly.
With a set of heads like this, you should be able to run 13's with a stock Toronado, or 442 cam, and some tuning.
JMO
Jim
Talk to your machinist about prices.
If he is that expensive, then go Edelbrock.
Remember, Edelbrocks will require some extra's too.
Rockers, pushrods, head bolts will add onto the price, and they still do not flow any better than stockers, until they get ported.
If you can not get the C heads bolted on with 2.072's in them for under $750, you should find another machinist.
That is a far cry from the near $2K to get the Edelbrocks running.
A 2.00 inch valved head usually flows around 205 max on the intake side of a BBO head, and the 2.072 will get you around 240-250 cfm if done correctly.
With a set of heads like this, you should be able to run 13's with a stock Toronado, or 442 cam, and some tuning.
JMO
Jim
Last edited by Warhead; July 6th, 2009 at 04:58 PM.
July 6th, 2009, 05:43 PM
#12
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Thread Starter
Join Date: Dec 2008
Location: Somerset Wisconsin
Posts: 1,167
Rbuild the C heads, and get some 2.072 valves.
Talk to your machinist about prices.
If he is that expensive, then go Edelbrock.
Remember, Edelbrocks will require some extra's too.
Rockers, pushrods, head bolts will add onto the price, and they still do not flow any better than stockers, until they get ported.
If you can not get the C heads bolted on with 2.072's in them for under $750, you should find another machinist.
That is a far cry from the near $2K to get the Edelbrocks running.
A 2.00 inch valved head usually flows around 205 max on the intake side of a BBO head, and the 2.072 will get you around 240-250 cfm if done correctly.
With a set of heads like this, you should be able to run 13's with a stock Toronado, or 442 cam, and some tuning.
JMO
Jim
Talk to your machinist about prices.
If he is that expensive, then go Edelbrock.
Remember, Edelbrocks will require some extra's too.
Rockers, pushrods, head bolts will add onto the price, and they still do not flow any better than stockers, until they get ported.
If you can not get the C heads bolted on with 2.072's in them for under $750, you should find another machinist.
That is a far cry from the near $2K to get the Edelbrocks running.
A 2.00 inch valved head usually flows around 205 max on the intake side of a BBO head, and the 2.072 will get you around 240-250 cfm if done correctly.
With a set of heads like this, you should be able to run 13's with a stock Toronado, or 442 cam, and some tuning.
JMO
Jim
Thanks to all you guys.
Dave
July 6th, 2009, 06:17 PM
#13
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Join Date: Aug 2007
Posts: 2,250
Will these "ready to go heads" have large valves, good guides, a multi-angle seat and bowl work? If not, better to work the ones you have and know what you have.
Guys are all the time saying that putting money into iron heads is a waste. But, look at it this way, $800 does a very nice job on your heads vs the cost of E-brocks. Would the extra grand well spent (quality converter, lighter pistons, rear gear, etc ) give you more performance than the E-brocks will over your worked irons? IMO, yes. Now, once you are seeking serious power levels, the aftermarket heads win out, but for your modest goals, the iron heads will be fine. Again, IMO.
Guys are all the time saying that putting money into iron heads is a waste. But, look at it this way, $800 does a very nice job on your heads vs the cost of E-brocks. Would the extra grand well spent (quality converter, lighter pistons, rear gear, etc ) give you more performance than the E-brocks will over your worked irons? IMO, yes. Now, once you are seeking serious power levels, the aftermarket heads win out, but for your modest goals, the iron heads will be fine. Again, IMO.
July 6th, 2009, 07:42 PM
#14
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Location: Chicago
Posts: 5,468
I'm with Captjim and Warhead. Irons are the easiest/cheapest way to go for a high 13.
Hell, if those C's were in running condition Stock. You could turn high 13's with a 3.08 1 legger and your comp 268H no problem. Piece of cake.
January 7th, 2011, 10:36 AM
#15
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Join Date: Apr 2008
Location: Puyallup
Posts: 1,146
Found this post by searching bigger valves as I am talking to my machinist
about adding bigger valves in my C heads. About $80.00 more.
I'll probably bite.
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