[Formulajones]

Originally Posted by JLMounce

Basically what I'm wanting is a reliable engine that will motivate the car well and run on fuel from any gas station I visit.

This one really caught my attention. Plus the fact that you say your at 11:1 right now with an iron head.

I believe Colorado has the same 91 octane we use here in AZ. It's not the best. Being able to drive the car long distance opens a can of worms as well, as you never know what you get from one station to the next. In other words you need a cushion.

I honestly don't think the RA IV cam swap will bleed enough pressure to run straight pump gas with the ignition timing where it needs to be on an 11:1 iron headed motor. I still think that's going to be borderline for pump gas and finicky to tune. 10:1, maybe, 11:1, I don't think so.
With that said, I can't see the smaller 2802 cam helping you either, that cam is already small for a 455 anyway.

If it were mine I'd be doing cylinder heads. Since this isn't a stock appearance build I'd likely go for a set of aluminum heads that will drop the compression to 10:1. With aluminum at that compression, even with a mild cam that provides excellent drivability you could run the engine on cat pee and stop worrying about it.

How you have the rest of the car setup plays a big roll as well, just as mentioned. No rear gear in the car lugs the engine, how hot you run the engine, AFR is just as important, etc....Unless you really want to play with all those things, then I'd give yourself a lot of detonation fudge room on the engine setup.
I can tell you from my own experiences using this crap gas and owning several different cars. The cars I have with aluminum heads that are pushing the compression ratio at 10:1 or more, run flawless on 91 pump. The cars I have with iron heads that hover between 9:1 and 10:1 have a tough time with 91 pump and I have to watch the tune pretty close. Especially in the summer when temps are 110+

[ta man]

Originally Posted by goatless

It's used parts. Used always costs less than new.
It doesn't mean they're not good parts, it just means someone else took the $$ hit of buying them new. Heck, sometimes they're not even used- people change their direction on a build and just want to get some of their $$ back instead of letting them sit on a shelf.

Personally, I think buying used heads (from a reputable seller) that have been done by a reputable shop, with known parts is great way to get where you need to be without spending a ton of money.

I agree....Also everyone does realize the OP is running 72 cc heads on a 455??He may be over 12 to 1 for compression!
A purchase of a good known set of used iron heads is a good choice....and can be resold in the future for the same purchase price.I'm sure there is a set here somewhere for under $500...

[Half-Inch Stud]

Ported Heads is (like) the first form of Boost.

[PunchT37]

Ported heads ARE worth the expense. Pontiacs already have "small block" heads on big cubes.

So, appearance and cost come in. Aftermarket heads are more worth it these days than stock castings. Stock castings are all one had to work with back in the day.

Iv`e got some hand ported Dave Bischop 6x heads on one of my engines. Before he had the cnc. $1700. Prolly wouldn`t go that way again today unless I was going for car show purist points.

Cost, someone has some ported cast iron heads for sale or edelbrock heads for sale at less than new cost. But, most or all alum. heads will prolly be round ports as they have been out the longest. So, figure different headers in the cost.

So, maybe a set of used cast ported or used KRE D`s. If I went for a new port job today, it would be on new alum. castings.

[steve25]

I 'am gonna open the flood gates again with this comment again to some extent!

1) Cylinder head flowing 260 to 275 cfm, iron or aluminum with no more than 185 CCs of intake port volume ,minimum 172 CCs.

2) Cam, no more then 245 @ .050"

3) compression 9.5 for iron, 10.8 for aluminum.

The Crossover / rpm CID point for needing more port CC's with a 400 is 5800 rpm.
That same point with a 428 is 5400 rpm.

If your motor does not spend much rev time above these rpms then running a 215 CC intake port is counter productive will leave you with less torque and HP then you could have had otherwise below the rpms I posted!

Motors with the stroke of a 455 or greater can make use of the 215 CC ports .

[JLMounce]

Originally Posted by steve25

I 'am gonna open the flood gates again with this comment again to some extent!

1) Cylinder head flowing 260 to 275 cfm, iron or aluminum with no more than 185 CCs of intake port volume ,minimum 172 CCs.

2) Cam, no more then 245 @ .050"

3) compression 9.5 for iron, 10.8 for aluminum.

The Crossover / rpm CID point for needing more port CC's with a 400 is 5800 rpm.
That same point with a 428 is 5400 rpm.

If your motor does not spend much rev time above these rpms then running a 215 CC intake port is counter productive will leave you with less torque and HP then you could have had otherwise below the rpms I posted!

Motors with the stroke of a 455 or greater can make use of the 215 CC ports .

That's one of the things I'll ultimately be after. I run a 3.73 ratio in the rear along with 26" tires, so I need rpm on the top end. While the car isn't currently seeing any road track time, that's the ultimate plan and several of the tracks around my area I'll be at the mechanical speed limit of the car fairly quickly.

Ultimately I'd like to be making in the 550hp range with an effective rev limit of around 6000-6200 rpm. A good sized roller and aluminum heads are definitely going to be necessary. Barring going in to debt to buy them, it'll take a bit to save up for those items.

[tom s]

for a desired HP goal,the better the head,less cam will be needed.Tom

[torqhead]

Originally Posted by JLMounce

That's one of the things I'll ultimately be after. I run a 3.73 ratio in the rear along with 26" tires, so I need rpm on the top end. While the car isn't currently seeing any road track time, that's the ultimate plan and several of the tracks around my area I'll be at the mechanical speed limit of the car fairly quickly.

Ultimately I'd like to be making in the 550hp range with an effective rev limit of around 6000-6200 rpm. A good sized roller and aluminum heads are definitely going to be necessary. Barring going in to debt to buy them, it'll take a bit to save up for those items.

Jason, Interesting your goal is exactly where I'm at today with my car. I run 3.73 Moser with 29" tires and my motor is built with rev limit at 6200. The numbers you're looking for will just get you into the high 12's at our altitude.

[JLMounce]

Originally Posted by torqhead

Jason, Interesting your goal is exactly where I'm at today with my car. I run 3.73 Moser with 29" tires and my motor is built with rev limit at 6200. The numbers you're looking for will just get you into the high 12's at our altitude.

I'm not terribly concerned with quarter mile figures. I enjoy a good blast down the strip, but I enjoy road course tracking since I got into it back in 2006.

The quickest I've ever been down the 1320 was in my previous 2003 Cobra and that was a 12.83@116, so nothing barn burning.

[Pontiac Derek]

Hell Yes its worth it and I haven't built but one engine in 10 years that had no port work.
Dave at SD imho is Offering the most Head For the money!
Everything is machined, new seats, new guides, set up for spring cups, Custom Back Cut Ferrea or Manley Valves, Custom Competition Valve job, Viton Valve Seals not the leak prone teflon or umbrella junk, 100 % cnc Ported and the HAND FINISHED Short Turns, Virtually any size chamber, all three surfaces are milled, decks cut to a finish fine enough for MLS Gaskets, ARP Screw in Rocker Studs, any spring configuration, etc
My 17's flow 270 at .600 lift exhaust is 220 at .600 lift
Even at .500 they do 260in 200ex !
These Heads Beat out of the Box Edelbrocks and KRE D ports by quite a bit, Dave has done the Back to Back testing and he isn't biased He Wants what actually works and if its his stuff that is kicking butt he doesn't rest on his laurels
He continues makes his stuff better!
Now i have been Quoted By other Big Name Shops "i wont name names" but i was quoted between 2800-3000+$ using my cores!!!
Kinda shows you How Hard SD has worked to allow the Average Joe to build a nice Pontiac Engine!

[ta man]

Originally Posted by torqhead

Jason, Interesting your goal is exactly where I'm at today with my car. I run 3.73 Moser with 29" tires and my motor is built with rev limit at 6200. The numbers you're looking for will just get you into the high 12's at our altitude.

Why are you guys setting the cars up like a 400????6200 rpm for a 455?I'd swap the gearing down to 3.42's and use 5500 as a rpm limit...unless you have a 455 that peaks at 6200 rpm...which I would guess would be 650hp? and built that would make sense.

[JLMounce]

Originally Posted by ta man

Why are you guys setting the cars up like a 400????6200 rpm for a 455?I'd swap the gearing down to 3.42's and use 5500 as a rpm limit...unless you have a 455 that peaks at 6200 rpm...which I would guess would be 650hp? and built that would make sense.

Well realistically, I'm simply working with what I have for the time being. 99% of everyone here runs these things in a straight line and having larger diamter tires helps things like slowing down moment of inertia and creating a larger contact patch for a drag strip launch were such things are crucial.

I on the other hand have aspirations of putting the car on the local road courses here in Colorado with the NASA Rocky Mountain chapter. I want wide, small diameter tires because it helps wheel acceleration and punch coming off the corner. At the same time I need the extra RPM for the front or back straight were a 3500 lb 400-450 hp car is going to be running 125-135 mph. With a rev limit of 5500 rpm, 3.73 gears and 26" tall tires you're at the mechanical limit of the car at about 120mph in your 1:1 gear.

This thread was more about budget items, but without budget constraints I wouldn't have a 455. I'd have a 455 based 434 and I'd spin it to 7000 rpm.

[i82much]

Have you done the calculations on how much it would cost you to mix race gas for a few years until maybe you could save up for aluminum heads? Just throwing it out there. You might be surprised at the numbers depending on how little you drive your car.

Say you drive 1500 miles per year and get 15 miles per gallon, so you are looking at 100 gallons of fuel. At $3 per gallon for unleaded that is $300 bucks. If you ran 1/4 race gas and 3/4 unleaded, you would need to buy 25 gallons of race gas, say $15 per gallon (total $375), and 75 gallons of unleaded (total $225). In that case, another $300 per year would keep you going for a few years.

I am not certain about my math, I don't know how much you drive your car, and 25% race gas may not be enough, but I guess it was worth throwing the theory out there for you.

[JLMounce]

Originally Posted by i82much

Have you done the calculations on how much it would cost you to mix race gas for a few years until maybe you could save up for aluminum heads? Just throwing it out there. You might be surprised at the numbers depending on how little you drive your car.

Say you drive 1500 miles per year and get 15 miles per gallon, so you are looking at 100 gallons of fuel. At $3 per gallon for unleaded that is $300 bucks. If you ran 1/4 race gas and 3/4 unleaded, you would need to buy 25 gallons of race gas, say $15 per gallon (total $375), and 75 gallons of unleaded (total $225). In that case, another $300 per year would keep you going for a few years.

I am not certain about my math, I don't know how much you drive your car, and 25% race gas may not be enough, but I guess it was worth throwing the theory out there for you.

Yes. at a 50/50 mix of 91 and 100 octane, it would take several years of fill-ups before the cost would equal a set of aluminum heads.

That's not really the concern though. The concern is that 100 octane fuel is not readily available. In Colorado there is only one fuel station that carries it. Fortunately I live a 1/4 mile from that station. The only other places in Colorado to get it are through performance retailers in bulk.

Even at a 50/50 mix I still have to neuter the tune so much to get it to stop pinging at WOT that the engine runs hot. So while financially it may make sense to just keep mixing, it's still not a solution.

[torqhead]

Originally Posted by ta man

Why are you guys setting the cars up like a 400????6200 rpm for a 455?I'd swap the gearing down to 3.42's and use 5500 as a rpm limit...unless you have a 455 that peaks at 6200 rpm...which I would guess would be 650hp? and built that would make sense.

My motor was designed with 5800 RPM peak horsepower. I probably could have gone with a taller gear but man I sure like how the car runs when I want to play, also I have a OD behind it.

[torqhead]

Originally Posted by JLMounce

Yes. at a 50/50 mix of 91 and 100 octane, it would take several years of fill-ups before the cost would equal a set of aluminum heads.

That's not really the concern though. The concern is that 100 octane fuel is not readily available. In Colorado there is only one fuel station that carries it. Fortunately I live a 1/4 mile from that station. The only other places in Colorado to get it are through performance retailers in bulk.

Even at a 50/50 mix I still have to neuter the tune so much to get it to stop pinging at WOT that the engine runs hot. So while financially it may make sense to just keep mixing, it's still not a solution.

Yep, it's a nuance in Colorado to find any decent fuel. Back when I was dealing with the same issue I used to have to make a 40 min. drive to Arvada to get fuel and bring it home, you got it easy!!! lol

[Boostedbird]

Have you looked into water/meth. It isn't a bandaid. It's a fuel and more. It's basically windshield washer fluid and water. Every gas station has that stuff. A few of my boosted buddies use it. I have it on my car, but haven't used it yet. It is a solution. Every issue on this board seems to lead to everybody saying to detune, put highway gears in and just drive it. I don't get it. It's kinda hard to outrun people with 350hp. Anyway, good luck with it.

[wovenweb]

Originally Posted by HWYSTR455

... some silver bullet.

Not a single word said yet...he is in Colorado and everyone knows the Silver Bullet was born in the Rockies. Coors Light that is.

[JLMounce]

Originally Posted by Boostedbird

Have you looked into water/meth. It isn't a bandaid. It's a fuel and more. It's basically windshield washer fluid and water. Every gas station has that stuff. A few of my boosted buddies use it. I have it on my car, but haven't used it yet. It is a solution. Every issue on this board seems to lead to everybody saying to detune, put highway gears in and just drive it. I don't get it. It's kinda hard to outrun people with 350hp. Anyway, good luck with it.

I haven't. It might be worth looking at, but I'm trying to make the process simpler.

Originally Posted by wovenweb

Not a single word said yet...he is in Colorado and everyone knows the Silver Bullet was born in the Rockies. Coors Light that is.

I'm still researching and getting opinions. im more of a craft beer guy anyway...

[JLMounce]

Just wanted to update this thread. After talking to several people, taking into account opinions here I went to work trying to get the car to a place where it'll be okay for this upcoming season.

I'll continue to mix fuels through the summer to help the detonation out. I ended up pulling total timing back to about 31 degrees, then adjusted the vacuum advance lockout to give me a couple more degrees during cruise. This has given me the bandaid of having the timing the engine wants to keep it cool while cruising around and not hammering the rotating assembly at wide open throttle. I also modified the tune in the EFI to deliver a richer mixture of around 11.6:1 at wide open throttle.

Over the winter I'll be going to a set of aluminum heads and a hydraulic roller cam. I'm leery of continuing to run a flat tappet cam because of the amount of ZDDP required which can fowl oxygen sensors.

I just wanted to say thanks for everyone that replied to help out on this.