[MetalHead175]

Hey guys...Been away from the forum for awhile, got married, have a kid on the way, switched jobs, and been going to school...kept me away from getting the bird done but that is changing. At the end of the summer, I'm resurrecting my roots blown 871 455 Idea and have some questions about it. First: I was thinking about buying some Eheads at 85 cc chambers...given a 15cc dish that puts my 455 at 9.5:1 compression...is that too high? If so I may be forced to use my 4x heads for the time being (would that really be a bad idea? It would save me money for sure). Also would you guys upgrade to a Hydraulic roller cam, or still use a hyd flat tappet? One more thing too...Are KB Forged pistons any good? I was thinking about a set of them as a more affordable option to the Ross's. Thanks guys, I'm excited to be back into this again.
-Jason

[thadeal4real]

Originally Posted by MetalHead175

I was thinking about buying some Eheads- YES
my 455 at 9.5:1 compression...is that too high? -NO
use my 4x heads -NO
upgrade to a Hydraulic roller cam -YES
Are KB Forged pistons any good?-I would get lightest possible for budget

good luck

[aronhk_md]

I disagree......9.5 to 1 may indeed be too high, even though they are aluminum heads. You are probably better off using the 4x heads.....port them if you can even if you do it by hand. UNLESS you buy dished pistons.

Keep in mind most of my experience is through reading...I have no problem admitting that. But I DO have experience with research on a professional level, so I've become pretty good at weeding out the BS you can read all over the internet and finding solid supported facts

The turbo 455 I just bought from Mark made over 1000 hp with 6x heads. The e-heads would be nice, but if you do use them get DISHED pistons. If you do that you could keep the compression at 9:1 or less, and breathe when you step on the pedal.

Why play with fire when you have alternatives that work?

As for cam, there are some very knowledgeable people here that I'm sure will jump in.

[TIN TIGR]

first, k-b pistons are ok..but the real ? is how fast ya wanna go..it sez pro street..if ya wanna drive it, dont spend money..it will go stupid fast with a 8-71 on a stock 455 engine..been there, done that..

i would use a cheaper, home diddled iron head..the blower will make that work..run flat top pistons with a big chamber..instant blower motor..

buy some good rods, balance it, and buy a blower hub..run the easy flat tappet hyd..no issues, and cheap cheap..

if ya cant make 700 hp or more, ya need a new hobby..

do they have e-85 in redding yet?..if so, up the squeezee and use it..marvelous fuel..

need a short block?..i got a couple going together that would work..

[MetalHead175]

Thanks for the great answers guys, I appreciate the help. Tin Tigr, you really think it can have 700 horse with just the 871 on the 455 and a mild cam?

Nah I haven't found E85 up here yet, but that doesnt mean we dont have it. I currently have a 74 455 that's completely stock, stock bore, that doesn't even need to be bored, with a set of 4X heads...figured the compression to be about 8 to 1 or so. How much would you be asking for one of your short blocks? Just curious...and whats all been done to them? I will probably just use mine, but I'm always up to persuading

BTW AronHK that car is beautiful...Car porn for sure =D

[TIN TIGR]

yes, 700 is very do-able on a stock headed 455..the 8-71 makes a lot of air..i will pm you about engines..and find e-85 if ya can

[69Goat1]

I run a fully stripped Magnesium cased ED Pink 8-71 on my 462 with flattop SRS forged pistons and ported 87 CC E-heads - I run it on 110 octane fuel and it makes stupid power... I have 2 suggestions for you.

1. Run a very good Multi Layer Steel Head Gasket - I run the Cometic MLS.
2. Make SURE you run a double keyed steel crank hub and have your crank double keyed. How I know is because the Balancer Lower Blower Pulley assembly becomes quite the missle when the factory single keyway gives up and the crank bolt unscrews...



That is a picture of an 8 quart pan and I got lucky that it came off on the return road instead of at 145...

[69Goat1]

This is the car...



With hood...

[aronhk_md]

MetalHead......thanks for the compliment. I cant take credit....Mark L. built the car and I just bought it. I am making changes to make it my own and hopefully improve it for my purposes though.

700 hp should be very easy to hit with an 8-71 on that engine. Unless you want to run 110 octane gas like 69Goat1 though, I'd choose the lower compression route.

My car hit 1064 hp for Mark at the crank (886 at the wheels) with 15 lbs boost on 91 octane with an intercooler. I'm adding methanol/water injection for safety reasons as I'm probably at about 9 to 9.1:1 compression and I want to avoid all possibility of detonation. The side effect is it will probably add 70-100 hp. Terrible scenario...lol. Ideally I'd like to lower compression to around 8.75:1, but for now I'll just be careful to keep it rich, the and timing safely back.

Good luck, and visit some of us at the boosted section of Pontiaczone.com forums as well.

[Torment]

9.5:1 would be excellent for E85. Most I ever did with 110 octane was 8.5:1 on a 455 w/8-71. I imagine you could run at 9.5:1 but you might be limiting yourself on blower drive - I'd say it would be less than ideal and you'd be in a race gas combo all the time. At 8:1 you can under drive 5% or so and run 92 octane, or over drive and put in some good fuel. A hydraulic will make great power for a street rod, if you're going racing go solid roller. Great suggestions by 69Goat - I'd also suggest both ideas - and yes it'll be pretty hard not to make 700hp with an 8-71. Unless you start with too much cr for your fuel

If it makes you feel better about the 4X's my home ported 48's ran harder than Eheads on my old blown 455...

[MetalHead175]

That 700 horse thing had got me pretty pumped up...that's a lot of power and for not a lot of money in all reality. Another question that I've googled and not gotten an answer is, would an intercooler be worth the money? And what kind of horsepower numbers would one gain? Thanks

[aronhk_md]

My understanding of intercoolers with roots type blowers is that they are very expensive. Of course they will add power. So would a simple and cheaper (relatively compared) methanol injection system. Is it worth the cost? Probably not if you have any kind of budget. Also if you keep the compression low using those 4x heads there'll be no absolute need.

Lots of guys run down to 8:1, but I think by that point you are losing power that you could have had at a very safe 8.5:1. So in my opinion you are better off spending the money to say have the heads milled etc to get that perfect compression ratio, or spending it elsewhere in carburetion or fuel injection than in an intercooler. But thats just my opinion.

[Torment]

Roots intercoolers are pretty common in marine applications due to the readily available source of fresh cool water to run through them. The challenge with an automotive application is maintaining a cool source. In a drag only deal this could be accomplished readily, but for continued street use a bit more difficult. Also considering the packaging arrangement of a roots intercooler - between the manifold and blower customarily - you're available core surface area is limited. Google "Superchiller" and you'll see any number of companies that make a variety from expensive to very expensive depending on the parent material of the core itself. Good luck.

[MetalHead175]

AronHK: 880+ at the tires is pretty impressive dude, is it streetable or a drag only car?
69Goat1: That's a beautiful car, good thing that snafu didn't jack up your car anymore...I had a 68 GTO and loved it.
So kind of as I thought, a roots intercooler for my application (street/strip) really isn't going to be needed. They seem to be extremely expensive and in my opinion not entirely worth the return. I could do with 700 horse at the moment...that into the 11's at least in the quarter...thats cool with me

[aronhk_md]

My car is a street car. When I picked it up a few weeks ago after its journey east from AZ, I took a chance with an unknown car and drove it home about 300 miles.....almost 7 hrs with a little traffic. At first the temp was around 195, but since then it barely budges above 180, so maybe I had a sticky T-stat.

Thats the beauty of turbos and superchargers. You can use a cam thats liveable on the street, and 91-93 octane if you plan the compression ratio right. The cam in my car barely has a lope, and if I didnt know better theres no way I'd believe the #s it put out. It doesnt have that earth shaking, barely lit idle. Of course getting into the boost lets you know really quick. Once I get the piping hidden back under a stock hood and shaker this thing is going to surprise people.

[SupergasDil]

Metalhead,
I have had a fair amount of street blower experience and I'm putting together my old 474 combo with a solid flat tappet (saves a bunch of money over a roller)and a set of unported 6H heads ( saves a bunch of money on aftermarket) and a couple of 850 double pumpers. My thoughts for a street strip deal using an 871, you don't need to do all kinds of trick stuff because the blower makes a lot of power. I'll help you however I can if you want to call me 918-340-3283

[Torment]

Years back I went 9.76 at 3700lbs+ with a 455, iron heads, flat tappet cam, pair of 850's and an 8-71 street blower. Drove the wheels off that combination on the street. I'm sure many have done much more, the point being however you can have a lot of fun and make some pretty good hp with a real simple street/strip 8-71 roots combo.

[MetalHead175]

That's an awesome time for a street car. I can't wait!
Dil: When the time comes, in a couple months after fire season starts, I will totally give ya a ring, I appreciate the offer for help
I kind of want that shake the earth, lopey idle though =D I lovvvvvvve turning heads with a thunderous lope. What cam would you guys suggest to achieve such greatness?
PS: If I don't respond till Sunday afternoon, it's because I'm going backpacking, not because I'm avoiding the forum

[Torment]

Actually in practice you'll find a Roots supercharger will really smooth out the idle of a cam that would otherwise be considered 'too big' for the combination.

That said... once you nail down the other details of your build and goals and share them with the board members, you'll get plenty of good suggestions on cam selection.

[69Goat1]

Update on mine... When I spun the balancer off the crank it was finally yesterday determined I need a new crank if I am going to run it blown but on the other side of that is that the rod and main bearings are both showing the affects of the boost from 1 pass - it was determined probably another 2 passes like the one I made and it would have spun some bearings... The rod and main journals are fine, block is fine so until I can build a dedicated Blower motor I am saying 10.25:1 is too much for 110 octane and 12% overdriven with a fully stripped 8-71 competition blower! People that know me know that if I can't throw at it what I want I don't want to mess with it so I decided to put the engine back together as a little daily driver un-blown for now... I mean... if it is blown it better run deep 9's or faster or it ain't worth messing with...