[demonic68]

Hello there every one I am a newbe that has some boosted Pontiac questions. I have a 1968 Pontiac Lemans with a I believe a 72 455 that I am in the process of getting ready to turbo looking for some advise in the cam / motor / heads / turbo size for a single turbo build area. So let me post up what I have planned out so far for the build I am looking for a 8 to 9 sec street car so please let me know if I am on the right path.


For the bottom end I am looking at Butler/Ross pistons h beam rods
not to sure about going 4 bolt main yet suggestions?

Heads I have 6x or 4x heads not sure witch pair to use but which ever will get a port and polish job until I can drop some cash on some really good heads

Cam I really have no clue lol

Intake Edelbrock vic vr with csu 750 blow through

Header I have been looking at Aronhk's that he posted

Turbo Borg Warner S475 ?

Any help or suggestions would greatly appreciated

[jdw_poncho]

Forged crank and better rods. Dont use the common eagle h-beam rods, look at crower or olivers. Buy the est you can can afford. You dont want all of your parts at the ragged edge of what they can handle.

4- bolt - YES and fill the block

6X-8 or find a used set of e-heads

Cam- Call butler with all your engines spec's/car weight/HP and boost levels, most likely it will be under 230 duration on a 114 lope sep

intake and carb- yep, dont even worry about porting it. Better to go megasquirt if you ave any electrical exp

Headers from Aron- Yep- But you will need to fab up cross over (2.5") and a merge with a waste gate. consider the room you need to run a single exuast pipe down past the motor. My 69 does leave enough room to run a 3.5" -4" pipe next to the motor. But I built the headers so that might have been why I didnt consider it. Mine go out the front.
You will need to decide how the turbo will be supported. If you use the frame and have rubber mounts you will need a flex pipe. If you mount it to the engine you will need to keep in mind cracks could form if you dont design something into the system so it can grow when it gets hot. If not it will crack. Im assuming your wanting to use mild steel correct? Coat or cover with heat wrap, better to coat. Better yet to build a stainless log manifold with sch 10 weld els.

S480 will put you there plus some. I believe the last one I bought they mentioned 1200hp, but that stock block wont handle that very long without a lot or prep work. I dont know your background so you might consider keepig it under 800hp??? Or buy a 59 389 block and search what some of the guys are using them for. I would be concerned about using a stock block running 8's. If your car weights 3500 with you in it thats a lot of HP for a stock block.

Keep waste gate placement in mind. You need to size it for that size of engine. I put two 60mm n my 507. Im sure one would work just fine if its in the proper place.

You'll need a intercooler unless your running E85 or a meth spray system. I had a tough time keeping the IAT's down when I ran mine on gas without a I/C. It was orginally designed to run meth. I removed my core support and used the bumper brackets to hold the front fenders. This gave me enough room to add a big intercooler and the piping if I wanted it.

Buy a good carb hat from CSU, dont try to make one. They look good and seal up well.

Think about the oil drain back issues you might have. Can you weld? If so just modify a good canton pan with a AN fitting.

Dont forget, now that you have a big HP engine your driveline will need upgraded soon!! LOL Good luck, post a few pics when you get started.

[taff2]

My take on this,you're right there for a 9 second car with all the parts you've planned on. For an 8 second car you'll probably need to upgrade a fair bit if your car is heavy.
Block- 2 bolt with ARP studs should be fine, (half fill as JDW mentioned is a good idea) ,as should any decent set of aftermarket rods and pistons,you're not going to be revving the combo that high,probably 5800-6000 rpm. I used a set of BRC custom dished pistons from Pontiac Dude to keep my compression down to 7.75-1.
Heads- 6X or 4X will be more than ample at the HP level you'll need to make to run 9's(around 800 HP I'd guess), I run iron factory 96 heads(with quite a bit of diy porting though) and I expect to make 1200-1400 with these. Quite a few have made these figures with iron heads.
Cam- as JDW said ,go with the company you buy your parts from,they'll probably contact one of the major cam companies for a recommendation anyway. I got my custom flat tappet from Comp Cams through Spotts. You could contact the cam companies yourself .
Intake/Carb- yeah,Victor/ Torker 2 or any single plane will do,CSU 750 carb a good idea. A friend of mine bought a Domi from them and it has performed faultlessly,just a twiddle on the idle mixture screws was needed.
Headers-any set, including Aarons,will be fine as long as the primary tubes are not to big,probably 1 5/8" to 1 3/4" will be around about right.
Turbo-I understand the B/W S475 is ok up to a 1000 HP with the correct turbine size and trim. It's a heavy unit mind,50lbs or so, I had intended using a pair of these but couldn't justify the weight,went with a pair of MP T70's as they weighed just 20lbs each. A friend of mine bought a pair of Precision 76's through Travis Quillen (along with the wastegates/dumpvalves/custom roller cam etc) and these units are light and physically small for the power they will make.
There's a lot of knowledgable turbo guys on here so I'm sure you'll get many recommendations.

[BruceWilkie]

Originally Posted by demonic68

Hello there every one I am a newbe that has some boosted Pontiac questions. I have a 1968 Pontiac Lemans with a I believe a 72 455 that I am in the process of getting ready to turbo looking for some advise in the cam / motor / heads / turbo size for a single turbo build area. So let me post up what I have planned out so far for the build I am looking for a 8 to 9 sec street car so please let me know if I am on the right path.


For the bottom end I am looking at Butler/Ross pistons h beam rods
not to sure about going 4 bolt main yet suggestions?

If you keep it under 6000 a good set of H-beams will hold up and so should a well prepped factory N crank though forged is a better choice. Turbo's with a safe tune are not as hard on parts... 800hp NA takes a bunch more rpm(added stress) to hit that power level plus as Travis Quillen explains the exhaust back pressure acts somewhat like a shock absorber easing some of the stress. If block isnt drilled for 4 bolt go with splayed 4 bolt caps/studs. If already drilled for straight 4 bolt but 2 bolt caps adding straight 4 bolt caps may not offer any significant improvement over just using studs!
Block fill stabilizes the bores for better ring seal...doesnt really add to overall block strength. Partial fill cant hurt but watch your oil temps.

A turbo motor doesnt need to turn high rpm anyway... Several guys out there successfully at the 800+level with 2 bolt 455's and factory cranks. DONT trust the china castings they are not as high a quality as the factory N cranks. Forged is a good idea but not mandatory. Light Pistons and rods are a good idea and 2618 forgings are better up to the task as well. That said old TRW/Speed-Pro forgings have worked ok for some. Icon forgings wouldnt be a bad choice. Ross or Diamond or BRC might be better. SpeedPro Hellfire rings. Good oil system and pan with good oil control, proper oiling and return to/from the turbo.

Heads I have 6x or 4x heads not sure witch pair to use but which ever will get a port and polish job until I can drop some cash on some really good heads

Use whichever is in better shape. Stock they are near identical as far as flow. Years ago some 4x's were found to crack between the seats... IMO the ones that survived this long werent them! I'll likely be using ported 4x's(my 6x's turned into porting/cnc development pieces which we learned a few new tricks that will be used on the 4x's). If I do decide on aluminum the cv1 "retool" head gets the nod. (only Pontiac head made with 355 aluminum vs 356 for the rest. 355 doesnt get as soft at 300 degrees as 356... important for maintaining fastener torque especially center ex side head bolt.)
Dont use stock valves.(they tend to break especially with stiffer than stock springs) Stainless will do but better quality on the exhaust side is a very good idea. Boosted engines need higher rate springs than NA motors dont skimp on quality retainers/locks either. Unported will require alot more boost and detonation control for the power level you are seeking vs ported. (Boost psi is a measure of restriction to flow). Iron will hold your gaskets better than aluminum(cv1 better than edelbrock) and can be ported to level where 15-17lbs of boost should get you 1000+ hp with a good air/water intercooler (plus proper turbo sizing etc.). (CV1's would be more power at lower boost). (The 6x port that got developed is similar but better flows through the curve and peak than a sbc Brodix 11x! Perfect for a 400-455 based motor under 7000rpm)

Cam I really have no clue lol

Travis Quillen/Butler or call Bullet(Mark is the turbo grind guy) I'll strongly suggest solid lifter, flat tappet or roller. Turbo cams run wide LSA's, little overlap to underlap. Often larger duration on intake than exhaust. IMO most Pontiacs will do fine with duration the same/similar on intake/exhaust.
Furthermore picking the right compressor and turbine match is more important than the cam. Generally the turbo will follow what the cam does NA. tq comes in a little sooner and peak hp extends out a bit further. You dont need a monster cam. In fact a few yrs ago someone was running an 068 in a 400 running well into the tens 135 mph at 5000 rpm(cast rods)rev limit and a bit over 4000 lbs.

Intake Edelbrock vic vr with csu 750 blow through

A torker2, old HSD, or Tomahawk should get the job done. Manifold should be ported to meet and compliment the head flow. T2 doesnt have much material at top of port at the flange. The Tomahawk can handle 300 cfm. You may/may not need a Victor.

Header I have been looking at Aronhk's that he posted

Nothing exotic is needed. Homemade logs or even certain factory logs have been run at levels well above 1000 hp. Personally I wouldnt want less than 1.75" OD pipe. I wouldnt want bigger than 1-7/8 either. Try to keep id close to ex valve size. Smaller pipe is a crutch to a poor turbine match. Secondary piping should not be too small for the turbine inlet(restrict flow available) but too big will dampen response.

Turbo Borg Warner S475 ?

Bigger would probably be better. http://www.turbodriven.com/performan...6_wrsin=92044&
There are tutorials at the bottom of that page. Also when entering inputs if you mouse over the ? marks they will guide you to whats needed for input. Might take you awhile to figure this out and learn it but it will give you an idea of what BW turbo will get the job done.

Any help or suggestions would greatly appreciated

I think we can help you more with more specifics. What car, what transmission, what weight, street or race or both? Fuel? pump gas, E85, race gas methanol? Your ET goal is attainable. Is your chassis etc up to the task? Lots of things to consider here.

[demonic68]

Thank you guys. Jdw your info was really helpful . I have been around alot of high power cars for most of my life. Mostly road race type of stuff , but nothing like the power of a turbo v8 lol. I did plan on a intercooled set up; thought about air to water for about a day then thought I should stay air to air. I do have a older air bonnet the csu used to sell. From reading what both you guys are saying maybe I should go to 800 whp for now. How long with the right prep will the stock block hold 800 hp? The car is going to be a full stock interior car with a cage. I was also looking at a fab9 9 inch rear end, with 275 or 295 rear et streets for hook up. The car will be mostly my weekend cruiser and that I can go to the track with and try to blast some 9 sec ET's.

[demonic68]

Thank you Bruce; I am trying to set the car up for drag racing / street. I am going to take my time on the build to try and get every thing right. As far as the car its self it is a 68 Lemans 2 door coupe. The tranny is a TURBO 400 bop that I am having built. I will be looking for help on the stall converter to lol. I am not trying to go too wild with it as it was my first car got her when I was 15 I am now 37... My ultimate goal is a very clean fast street / drag car with full interior on pump gas I hope this helps. I am sure there are other things I am over looking.

[BruceWilkie]

I think you might want to swap to a 3" main block. Life of a 455 block is affected alot by rpm/stroke/power more so than 67-early 70's 400 block. Smaller mains = more metal in the block bulkheads and caps.
All 59 some 60 389 blocks are very beefy thickwall casting technique blocks.(All 59's use same casting number and were either 4 bolt main or 2 bolt with only drilling for 2 bolt. The caps on either are same OD your 455 (maybe a scratch more at the center) 5/16" more than a 400! The 59/60 journal bosses are deeper into the block(over an inch. Mine are 1.33" at the bore undercut!) than 400 or 455's plus there is a stiffening rib along the pan rail. Those blocks need an adapter to mount a modern bop bell pattern and serve as a starter mount. (I made my own and it will serve as a mid mount plate as well.) Excellent starting piece if you can find one.(I can make an adapter if you find one of these blocks) Later 389's got weaker as they went to thinwall casting technique starting in/around 61 though I have seen a couple of 66 389 blocks that were about the same as a 400. The 67 400 2 bolt blocks are typically beefier than later years 400's to about 70. Then there were some 2 bolt 400's through 74 that would be suitable as well. Avoid 400 castings ending in 557. Alot of 400's 68-71 were drilled for 4 bolt even if 2 bolt caps were on it. Very rare RAV 400 blocks and SD455 had a reinforced lifter valley and also shared the 59's bulkhead thickness and reinforcement rib but thet didnt have the thick cylinder walls/decks of the 59.
I see little need for stroke beyond 4.25 with a turbo. Especially in a stock block application. A turbo(s) can be selected/matched to hp desired so running a 3.75 or 4" stroke isnt really going to make it harder to acheive the power your looking for.

Way back in 93 Marty Pabalkyn(sp?) Used a 406 combo to make in excess of 1600 hp. 270ish heads(iron) billet crank, splayed caps on a well prepped 67 400 block. Non intercooled but methanol fuel, 38 psi at 7800 rpm. Motor went 3 full seasons and winter teardown found a crack starting. Another strength exception is Vin63, he has been running a funny car with a splayed cap early 70's 400 with CAST crank, supercharged and 15% NITRO at rpms up to 8600 and HP near 1800. His block life is shorter but his N crank has been around quite awhile. (He once tried a 455 but went to aggressive on the Nitro and only lasted a few hundred feet and broke crank and block. TUNEUP is likely main reason it failed)

So...800-1000 at the wheels is certainly doable with a 400-462 stock block combo so dont worry much about 50 cubes. Forged 400 cranks are harder to come by than other strokes. I am still debating between 3.75" N crank I have or buying a 4'' or 4.25" stroke forged. I dont see need to exceed 6500 rpm with any of them.
I think prep, extremely well balanced reasonably light rotating assembly and excellent harmonic control is the big key to stock block and crank life.(I'm going to use a tci rattler for harmonic control.) Conservative tune-up keeps it alive.

IMO as you get closer to 1000hp the large main blocks seem more of a liability when it comes to lifespan. But there are quite a few out there in the 8-900 range and a few over 1000. Regardless very few NA stock block 455's have lived long over 800 hp. Arons car has dyno'd over 1000 at the wheels(previous owner) the 455 is using BME aluminum rods. All that power hasnt been hooked hard or used alot either.
NA we all know its harder to hook a 455 than a 400... adding turbo to either makes it even harder. IMO 455 based stock blocks are best suited to heavy street cars running NA. Fortunately there were a bunch more 400's made than 455's and finding a decent core shouldnt be hard. There are plenty of buyers for your 455 and you might even find a trade.

I'll let others throw in there thoughts/experiences.

[demonic68]

Thank you Bruce lots and lots of helpful info in there sorry I can't more specific with my build I am still trying to learn I will start looking for a 400 block if I were to run stock exhaust manifolds what are the best ones to use? Or if I were to build my own logs is there a good DIY for it with pics?

[RUDOLFSSON]

Sounds like a very nice build.. Factory stuff and turbos can go very fast!!

[Paz.Ansley]

Based on my research, after a in foreclosure process home is offered at a sale, it is common with the borrower in order to still have any remaining unpaid debt on the personal loan. There are many lenders who try to have all fees and liens cleared by the next buyer. However, depending on specific programs, regulations, and state laws and regulations there may be many loans which are not easily resolved through the switch of financial products. Therefore, the obligation still remains on the lender that has had his or her property in foreclosure process. Thank you sharing your opinions on this website. wish you luck

[70 bird]

Originally Posted by Paz.Ansley

Based on my research, after a in foreclosure process home is offered at a sale, it is common with the borrower in order to still have any remaining unpaid debt on the personal loan. There are many lenders who try to have all fees and liens cleared by the next buyer. However, depending on specific programs, regulations, and state laws and regulations there may be many loans which are not easily resolved through the switch of financial products. Therefore, the obligation still remains on the lender that has had his or her property in foreclosure process. Thank you sharing your opinions on this website. wish you luck

[demonic68]

Thanks 69gto been looking at your for some time extra bad a$$....