WA 2 FST

Hey guys,

Well as I'm digging more and more into this car, I'm discovering new things. I originally thought that this thing was a Gen VI engine with alum. heads swapped on it. Today I was trying to reseal the valve cover b/c it was leaking, so I pulled one of them off to check what kind of rockers I have (planning a cam swap) and to check the casting #.

Turns out the heads are iron. I thought so when I looked at the car originally, but this confirmed it. They are painted to match the engine block, and most of people who put on alum. heads do not paint them...so I thought that was strange. Anyway, they are casting # 14097088 which is GMPP part # 14096801. These are the standard 118cc rectangle port iron heads that come on the Gen VI motor. 2.19"/1.88" valves, 325cfm int. port volume.

Are they any good? I have a rectangle port low-rise alum. LS6 intake, and I want to keep that, but if I can find some better heads, then maybe I should consider some.

There is no reason to swap the cam with the current heads...now that I know it was specifically matched for these heads and compression ratio.

Also, I have piston #10215228. These are the stock forged alum. pistons in the Gen VI 454. With the 118cc chambers, they yield 8.75:1 CR. Are there some rect. port heads out there that have smaller chambers so I could bump up my base CR?

I'm not really disappointed...just trying to do my homework before making mods. The car runs very well, but I'm just planning my next move.

Thanks for any thoughts from you "tech" guys out there. :)

ken markusa

There's nothing wrong with those heads they will make plenty of power all they might need is a little porting in the bowl area and a nice valve job. As far as bumping up the C.R. it would be better to get a new set of pistons than changing heads because the open chamber has better flame travel across the piston face it depends on how much you want to up it.
Ken :cheers:

Corey_68

With the right cam and intake these heads will support 800hp.

These are the same heands I'm useing. :cheers:

427Hotrod

Those heads can easily be used to support well over 700 hp. It's done all the time. It all depends on what you want to do with it.

Before tons of heads flooded the aftermarket, those heads were used with .750 lift roller cams all the time and they made power past 7500 rpm easily on race engines around the country.

No reason to think that a good cam choice won't make fantastic power with them now. A little pocket porting and clean up just like most aftermarket heads will need, will produce a great bullet proof engine.

I love aluminum aftermarket heads ( they can all be had with chambers cast or milled to get you the compression you want- Edelbrock offers a 100cc oval port one and Brodix will mill theirs), but it amazes me how many folks are willing to drop $1500-2000 for a set of aftermarket heads when all they want is 500-550 or so HP. That can be made with GM iron oval ports with a hyd. flat tappet cam that could be used as a tow truck motor. In fact I have a buddy with a 10.5 comp. 502 and a Hyd roller cam that makes 625 on the engine dyno with GM iron oval ports.

Are aftermarket aluminum heads better and will they make more power? Sure...if you have the rest of motor setup to utilize them.

I don't know what all you're planning, but if it involves a less than 600-650 streetable HP 454, there is no reason to buy new ones except for weight savings unless you just want to. It can be done.

Just my opinion, but I don't like seeing people spend money they don't need to. Using the stock LS-6 intake is going to strangle anything you put on there, so the performance gain will be severely limited. Same goes for the exhaust side,especially with 454 cubes....it needs good sized headers.


JIM


[Modified by 427Hotrod, 3:33 PM 1/17/2003]

WA 2 FST

Jim and others...

THANK YOU for the good discussion! I appreciate the help, as I am new to BBCs.

I am not disappointed with the way the car runs now. I am not trying to build a 10-second car here. I believe it probably runs high-12s as is (its just a bit slower than my Z06 on motor, but quicker than my Lightning truck with is solid low-13s). I was originally just going to swap in a bit bigger cam.

If I'm right then it probably puts down ~300-310 Hp at the rear wheels (chassis dyno).

Here are the specs for the current camshaft. Remember its a hydraulic roller.

211/230 @ .050, .510/.540" max lift, 112 LSA

The thing is, I am going to have to change some of the valve train no matter what as this motor has bolt-down, non-adjustable rockers. So a switch to studs w/ adjustable rockers is necessary, and of course I'll need better valvesprings for a bigger camshaft. This may involve pulling the heads anyway in order to insure proper installed height of the new springs. ???

I would like another 40-50hp is all. My first thought was that I had heads that had the ability to outflow what the cam was offering. So I was just hoping to swap a cam in there and get closer to maximizing the combo. If I have to pull the heads, then I may get more radical with it all (but intend to stay with a hyd. roller cam).

However, all the combos you guys mention are motors with significantly more compression than mine. I really do not want to yank apart a motor that has 1000 miles on it. ;) That's why I was hoping I could get some heads that have smaller combustion chambers and raise the CR that way. I know I'm not going to get it to 10.0:1+...but a slight bump would be nice, and might be more suitable for a more aggressive cam.

Jim, my headers are 2 1/8" Hooker Super Comps. I would hope those would be pretty good for what I need. :)

As far as the intake...well, I do not want to cut the stock hood, or run an aftermarket one at this time. So the LS6 is about as good as I can get. I'm only looking to spin ~6000+rpm with a hyd. roller cam. I've heard the LS6 intake will be good for at least that.

So.... (I know I'm rambling)... do you guys think I should just install a bit larger cam now (currently the motor pulls to ~5500rpm)? Think it would be worth it even with stock castings and 8.75:1 CR? The car runs fine and is a street cruiser...not a 1/4 mile racer. But more power is always fun. I may just leave it alone and put a small 100-125hp shot of giggle-gas on it. That is not hard to do and would be very reliable.

Just a ?, but assuming 8.75:1 CR with 118cc head, what would a 100cc head yield as far as CR?

Thanks again. You guys are great.

Corey_68

2 1/8 hookers, are fine, I'm running them as well. I rebuilt the entire motor, going completely forged and stepped up to a 10:1 forged pistons. The dual plane LS6 should be good for 6,000rpms, but will fall off after that. If you are determined to run that intake I'd suggest porting it out along with the center divider to increase upper rpm flow. I also step up the cam some. You are running a roller, so you cam get away with a slightly more aggressive cam than if you were running a straight hydraulic.

I think a little porting on the intake and a more aggressive cam would really wake up the BB. You can always spray on top of that. :D
I plan to spray a 250hp later this year.

:cheers:

ken markusa

If you have an 8.75:1 engine with a 118 cc head going to a 100 cc head will give you a 10:1 C.R. i would try a different cam first.
Ken :cheers:

Flareside

Actually Wes, I think 10:1 without opening up your shortblock is very possible. Your stock head gasket is probably around .040" thick, so you can go with the copper .020" aftermarket gaskets for a 4cc compression boost.

On a 454, each 14ccs will be worth about 1 point of compression. You can get just about any compression ratio that you would want with the right gasket and chamber combo.

If I had your engine, and really only wanted an extra 50 hp, I would go for the thin head gasket, and the ZZ502 or similar cam. For about $200 bucks, you'll be there. As you can imagine, going beyond that requires a much more significant investment.

NHvette

I don't know BBCs much, but can't you have the head surface planed to bring
the chamber volume down a bit, too ? This with the thin gasket, intake porting,
and a new cam should put you past the mark that you are eyeing.

Good luck - tough decisions (when to stop). :seeya

WA 2 FST

Again, good input here guys. Thank you.

The biggest question was whether these heads were worth keeping, and could (in stock configuration as they are) support more airflow that a larger cam could give me. It sounds like they can.

If I have to pull them off, then milling them is an option. Of course, I have to be careful there, otherwise I can have piston/valve clearance problems and also intake alignment problems. According to Joe's calculations, I guess if I milled them .020 (~4cc), I'd pick up ~.30 of a point in CR. Not a lot, but it would be _something_.

Of course getting a set of 100cc heads would put me at 10.0:1 CR and make better use of the more aggressive cam. :)

That's the thing. If I gotta pull the heads, it will be tough NOT to do something to the ones I have (which is $$), or sell them and buy some new heads (more $$ than the former option, but I also might be getting a better head).

A cam swap is not that big of a deal obviously, and I have to remove the intake so porting it at that time is very reasonable (per Corey 68...that's a good suggestion).

Or, just run a conservative shot of juice on it now and wait for a few years or so til I get bored and decide to build a serious motor. :)

Joe, I have never run copper HGs before, so please enlighten me. I thought these were typically "race" pieces and they would leak. Sorry if this is a dumb question. I'm used to using graphite gaskets on street motors.

Any more input is appreciated, but it sounds like I have a lot of options...one of which was my original one of just putting in a bit larger cam. That's all I was going to do, but didn't know if these heads could handle it.

Flareside

Wes, I've never used the copper gaskets on a big block (hopefully, the other guys will have first hand info here), but I have used them on the street in a small block with absolutely no problems at all (with iron heads). Just install them with a good gasket sealer. I believe the LS-6 454s used this type of gasket, so your local GM dealer should have what you need. If you go with aluminum heads, it's probably easier to get the chambers sized as you need and run a regular composite gasket.

Most stock GM engines have the pistons about .020" down the hole at TDC, so you shouldn't have any piston to valve issues.

EDIT: Found the gaskets, GM part number 14015351, .022 compressed thickness LS-6 gasket.


[Modified by Flareside, 10:44 PM 1/17/2003]

69ttop502

I think you are on the right track here. I am exactly where you are with the motor. I have a crate 502 with the heads you have that dynoed 353 at the wheels with the stock setup of 8.75 to 1 and hydraulic flat tappet as this is a Gen V motor. One thing to watch out for with those heads is when I pulled them off and was going to use them the chambers cc'd at 122 and an engine builder friend said that is very common with these heads. Yes they can make great power though. So with 122 cc chambers and my pistons measuring .017 in the whole my actual compression was way lower than the 8.75 to 1. I ended up getting 600 dollars for the heads on ebay (mine were also very low mileage) and buying a set of Brodix with 100cc chambers which after zero decking the block will give me 10.4 to 1 with the stock piston. Jim (427Hot Rod) helped me alot with my choices also. Bill.

WA 2 FST

Bill, great info! Thanks for sharing. :)

My only issue with the Brodix heads are the raised exhaust ports. I just bought these Hooker 2 1/8" sidemounted headers and they are for standard port location. So I really cannot run a head with raised ports.

My problem (being so new to this) is that I do not even know all the options out there! :lol: Basically, what I'm looking for (assuming I go with a different head, and I very well may not) is a rectangle intake port and standard location exhaust port with a 100cc combustion chamber (without having to mill the thing to death, which will create poor alignment issues with the intake, etc). Is there anything like this out there?

I'm not sure I want to take on this big of a project (and the $$ that comes with it right now) right now. I was looking for a decent bump in power by swapping the cam out. However, if I've got to have the spring perches machined etc (to get the proper installed spring height), and must pull the heads just to do a camswap, then it behooves me to consider all my options (even if they are more $$ initially).

WA 2 FST

Something else that concerns me is swapping out the cam and going bigger on an engine with relatively low CR. Too much overlap on a low CR motor will make it a slug. So maybe I should leave well-enough alone til I decide to take a bigger plunge (like Bill).

Of course, there's always a shot of laughing gas to use when I "need" it. :)

Marks69BB

Wes - Interesting thread as I'm struggling with what to do with mine as well. Sounds like your engine is the identical Gen V/VI version of mine. Re HP, you're dead on since I pulled 303hp/416tq (with a slipping clutch) at the wheels with the old hookerSC/chambered pipes. I have the Gen IV version of your heads with the same ~8 3/4:1 CR. If I'm not mistaken, your block has siamesed cylinders so you have alot of room to grow. Mine has JE pistons which according to the casting number JE says are for 500+CI so I suspect my Bowtie block has been bored up in the past but the cam seems like the original mild Hyd flat tappet. I won't know more until I pull the heads.



[Modified by Marks69BB, 12:06 PM 1/18/2003]

JoeC427

:iagree:

WA 2 FST

Hey Mark. Well, it will be interesting when I get this thing over to the dyno. I'm basing my estimate on several things, but I do think I have a pretty sensitve posterior as I've been in a number of cars that put out this type (actually more) of HP/TQ. I was telling a friend the other day that I bet its a 300rwhp/400rwtq motor as it sits. I do think its running a tad rich, but until I get on a dyno with a wideband A/F meter, it is hard to say for sure.

I change my mind everyday (as I get more info, things get more cloudy...but again, its nice to have options). Today I'm thinking 100-150hp shot of juice. The car is a pleasure to drive and I wasn't planning on going into the motor this early on in the game. :) The nitrous would just be there for grins when I "need" it. I have a small shot on my Z06, and do not abuse nitrous like you hear from people with the horror stories. For a cruiser, which this is, that might be more than enough.

I will be sure to let you know how mine dynos.

69ttop502

WA 2, I knew you were going to bring up the raised ports as I have so far avoided thinking about it as I also have new Hooker sidemounts. If you have to pull the heads off anyway I would suggest cc'ing them and measuring your deck clearance so at least you know exactly what you have. I have really researched this stuff well and the smallest chamber you can get with a factory head was I believe 108 cc. That was an aluminum rect. port GM Angle milled from Scoggin-Dickey. Angle milling can get your chambers easily down to this figure but you then have the intake fitting issues and valvetrain geometry as well as other things. I like the idea of running the real thin head gaskets as long as your pistons are in the hole enough to keep your quench big enough. Then a nice hydraulic roller with the help of all the experts on this forum could be found that would run well even with slightly lower compression. FYI Stahl makes a header to fit the raised port heads which I may end up doing instead of modifying the Hooker's. Let me know if there is anything else I can help with. Bill.

427Hotrod

For the money, you can angle mill the original heads and do some porting. They can make lots of power. The conversion to adjustable valvetrain is usually done with the 3/8" to 7/16" adapter studs that several folks sell. Not the absolute strongest setup, but cheaper and I haven't heard of any breaking yet.

On the intake fitment issues....if the machine shop you deal with does not know how to machine the intake face of the heads to fit with ANY stock intake, then get a new machine shop. There is no reason to whack up the intakes to fit a set of heads. The machine work needs to be done to the the heads so they will fit anything.

The 2 1/8" tubes do get pretty funky with raised ports. The AFR's are only raised .350 or so, so they might not be an issue. The others are usually .600-.750 range. That can be tough!

I'm with milling the heads, thin headgaskets get as near to 10-10.5 as possible.

Is the intake the "high rise" 427/425 hp one or the low rise "pancake" LS-6 type? I think most crate motors had the taller one. If so, I'd use it with a little port work. It can run 10's also! it won't be what's holding you back. The flat one is a whole 'nuther issue!


I still vote for a solid anything cam over a hydraulic anything cam!


JIM

WA 2 FST

Jim,

Thanks for your help and honest advice. Sorry, I'm being a sissy about the hydraulic roller setup. If I was gonna spin 7k rpm or more, then I'd go with a solid roller for sure. Maybe on another motor in the future. :)

Anyway, I'm afraid I do indeed have the low-rise LS6 intake. The casting # confirmed this (unless they are both the same, and the only way you can tell the difference is by visual confirmation). And while I'm a rookie at these carb intakes, I would say it is definitely a low-rise "pancake" looking intake. :( It's too bad, but it fits nicely under the stock BB hood (no L88 hood here), so I think I'm pretty much stuck with it.

I have already researched the adjustable rocker arm kit you speak of. Should be adequate for the lower revs I'm turning. Thanks for the confirmation on this.

I am definitely nervous about camming it up if I cannot also get the CR up some.