Heads before cam ??
#1
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Heads before cam ??
If I get my new heads before a new cam for my daily driver LT1 caprice, I plan to get a mild/moderate cam soon enough after, so what should I look for in my heads .
I currently have stock iron heads, so apparently the aluminum aftermarket heads will already be an upgrade . But not know much about the intake and exhaust lengths and timing, I don't know what decent specs I should look for when replacing to performance heads .
Or is it smarter to replace the cam first ?? Does either depend on the others performance more ? I also don't know what exactly I'm looking for n a cam yet either . I am doing my research, and figured I would put this thread out at the same time .
Thanks for reading .
I currently have stock iron heads, so apparently the aluminum aftermarket heads will already be an upgrade . But not know much about the intake and exhaust lengths and timing, I don't know what decent specs I should look for when replacing to performance heads .
Or is it smarter to replace the cam first ?? Does either depend on the others performance more ? I also don't know what exactly I'm looking for n a cam yet either . I am doing my research, and figured I would put this thread out at the same time .
Thanks for reading .
#3
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Personally I would gather everything up and do them together. You can check your valve to piston clearance if you have the heads off, and put a timing pointer & TDC mark on it while the heads are off. Do it once and right. You can verify your Optispark's timing by comparing it to your indicated timing on your scan tool. Especially it you ever go to an MSD Opti. :-)
Ported iron LT1 heads run great.
Ported iron LT1 heads run great.
#4
I feel its easier to replace the heads first as the oil pan can stay on. But from what i read the iron head LT1 outflows the aluminum head LT1. If u are looking for a mild cam and not having to bother with changing the valve springs try the GMPP #14097395 hyd roller. It is used on the RAM 350 and the 383 truck crate motors making 350hp and gobs more torque using vortec heads that are very similar to our LT1 heads in flow.
Yes if this was my first time cam change for less than 200 bucks i would use the GMPP #14097395 hyd roller and a gasket kit. It should be a great match for your engine and car.
Good luck,
cardo
Yes if this was my first time cam change for less than 200 bucks i would use the GMPP #14097395 hyd roller and a gasket kit. It should be a great match for your engine and car.
Good luck,
cardo
Last edited by cardo0; 12-04-2013 at 09:23 PM. Reason: wrong engine listed
#5
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If you plan on doing heads, do a cam at the same time. Just makes more sense to do it right while you have it apart.
I'd be looking for a set of ported aluminum GM LT1 heads from one of the reputable head porters. No need at all to go with aftermarket castings in your application.
I'd be looking for a set of ported aluminum GM LT1 heads from one of the reputable head porters. No need at all to go with aftermarket castings in your application.
#6
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Of course the best bet is to do it all at once but if that is not going to work out the cam is the better option.
The stock b-body cam wont support better heads well enough to make that swap worhtwhile.
The stock b-body cam is something like 191/196 0.418/0.430.
Karl Ellwein which most of you will believe tried ported aluminum LT1 heads with a stock b-body cam probably 10+ years ago and said it LOST like 2-3hp.
The stock b-body cam wont support better heads well enough to make that swap worhtwhile.
The stock b-body cam is something like 191/196 0.418/0.430.
Karl Ellwein which most of you will believe tried ported aluminum LT1 heads with a stock b-body cam probably 10+ years ago and said it LOST like 2-3hp.
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I would always do heads before cam, if doing both wasn't an option. A cam is spec'd to the entirety of the motor. You don't modify heads to fit a cam. I know that it might not be the best performance option at first, but it will yield better and cheaper results over time.
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#8
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I would always do heads before cam, if doing both wasn't an option. A cam is spec'd to the entirety of the motor. You don't modify heads to fit a cam. I know that it might not be the best performance option at first, but it will yield better and cheaper results over time.
The cam is the choke point on a stock LT1, not the heads.
#9
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Not true. Ran a best of 13.9 @ 100mph when car was bone stock at Texas Motorplex. Did LPE heads/intake, 1.6 rockers, Edelbrock shorty 1 5/8" headers into stock y-pipe with cats and ran a 13.2 @ 106. There are huge gains to be had with just changing out heads.
#10
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I ran 13.2 with a ZZ4 cam only setup 1 5/8" mids 2800stall 3.42s 28" tires.
Besides the b-body cam is a fair bit smaller than the f-body so still not talking apples to apples.
The duration difference on the intake side from b-body cam to f-body cam is similar to the difference of f-body cam to HOT cam.
Looking at it that way it seems kind of odd that given more compression and 91 octane the stock HP difference isn't greater between the two. IMO both cams are so mild and the heads good enough that as has been said the cam is the weaker link in stock form. Aftermarket cams offer a LOT more lift and faster lobes to get the valves open enough to start moving air.
Besides the b-body cam is a fair bit smaller than the f-body so still not talking apples to apples.
The duration difference on the intake side from b-body cam to f-body cam is similar to the difference of f-body cam to HOT cam.
Looking at it that way it seems kind of odd that given more compression and 91 octane the stock HP difference isn't greater between the two. IMO both cams are so mild and the heads good enough that as has been said the cam is the weaker link in stock form. Aftermarket cams offer a LOT more lift and faster lobes to get the valves open enough to start moving air.
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Stock LT1 iron heads have trapped 108 mph in cars heavier than yours.
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bowtie, you should read all of my post. My post was based on a one or the other right now. Everyone preaches about doing things right the first time but now it doesn't matter?? I understand why people leave forums....
#13
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But like others said, he should wait until he can do the cam at the same time.
Sorry if I offended, but I still have to disagree. "If doing both wasn't an option" ...... do the cam.
#15
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Believe what you wish. With times and mph like that in an F-body, you weren't even close to utilizing the potential of the stock heads. Your headers and rockers (you added cam ) were responsible for just about all of your gain. Did you tune it too?
Stock LT1 iron heads have trapped 108 mph in cars heavier than yours.
Stock LT1 iron heads have trapped 108 mph in cars heavier than yours.
I can't believe for a second rockers and junk Edelbrock headers were responsible for a 6mph gain. The Edelbrocks did nothing for that car. It may of had 1 5/8" primaries, but it was choked back down into the stock cats and y-pipe. No tune either.
It went like this:
Stock at the track mentioned 13.9 @ 100
Heads/intake/rockers/headers- 13.2 @ 106
all the above with LPE cam and tune- 12.5 @ 110
all above with Hooker LT's and ORY- 12.2 @ 114
all above with a 4.10 to 3.73 gear swap- 12.0 @ 115.5
Just imagine the results of that 108 car you reference if it were to of had a set of ported heads.
Last edited by SS RRR; 12-07-2013 at 08:23 PM.
#16
Easy fellas, any 2 mechanics can argue cams and heads all night long. What u need to realize is the OP had only 1 post and no responses or feedback here. I thought it was an intersting question for and iron headed LT1. But no longer worth a battle if the OP doesnt even participate.
I would like to see what that GMPP #14097395 hyd roller would do in a caprice,
cardo
#17
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And BTW, there was more than one car doing this. But I guess you can write us off as just crazy, after all, we were crazy enough to be running B-body cams too .....oh wait, I guess that had no effect since the heads are the limiting factor at the stock level
And ok, you got me, those were glory runs. Both cars trapped 103-105 mph on average summer days, various tracks, at 3900 and 4000 lbs.
The examples I've given are not a boast. It's to point out that some have "evaluated" heads more thoroughly than you have just by pulling more air through them.
Go back and read the OP's post. He's clearly at the elementary level in understanding all of this. I wouldn't mislead him that heads will have more effect than cam, just because it's something you've done in the past and validated it in your own mind.
#18
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I wouldn't mislead him that heads will have more effect than cam, just because it's something you've done in the past and validated it in your own mind.
You should perhaps re-read what I have said. There's nothing in there regarding how heads have "more effect" than a cam. I am only disputing your claim there is no gain to be had by just doing heads with stock cam. Since there are flow differences between iron and aluminum LT1 heads perhaps the gains on the iron heads aren't as significant. The only issue I believe you're crazy over is thinking my gains came from 1.6 rockers and shorty headers going back into stock y-pipe.
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That's fantastic. I have also heard of f-body bone stock cars running low 13's at (insert track here). Pretty sure you already know the vast differences in track results in different parts of the country. My car ran a best of 13.6 @ 102 at HRP when completely stock. Perhaps it could have run faster at a different track, however I am giving one track for consistency sake.
I can't believe for a second rockers and junk Edelbrock headers were responsible for a 6mph gain. The Edelbrocks did nothing for that car. It may of had 1 5/8" primaries, but it was choked back down into the stock cats and y-pipe. No tune either.
It went like this:
Stock at the track mentioned 13.9 @ 100
Heads/intake/rockers/headers- 13.2 @ 106
all the above with LPE cam and tune- 12.5 @ 110
all above with Hooker LT's and ORY- 12.2 @ 114
all above with a 4.10 to 3.73 gear swap- 12.0 @ 115.5
Just imagine the results of that 108 car you reference if it were to of had a set of ported heads.
I can't believe for a second rockers and junk Edelbrock headers were responsible for a 6mph gain. The Edelbrocks did nothing for that car. It may of had 1 5/8" primaries, but it was choked back down into the stock cats and y-pipe. No tune either.
It went like this:
Stock at the track mentioned 13.9 @ 100
Heads/intake/rockers/headers- 13.2 @ 106
all the above with LPE cam and tune- 12.5 @ 110
all above with Hooker LT's and ORY- 12.2 @ 114
all above with a 4.10 to 3.73 gear swap- 12.0 @ 115.5
Just imagine the results of that 108 car you reference if it were to of had a set of ported heads.
#20
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I had the wrong gears for the setup. The 4.10's were slowing the car down going past power peak before the traps. The 3.73's put the engine much closer to power peak when crossing the traps.