301 turbo MLS gaskets and 4340 forged billet internal balance crankshaft
 

Hello, all, I am new to this site, and am in the process of restoring a 1980 Firebird Formula with the original 301 turbo engine. This will be a resto-mod, but I have run into all kinds of problems finding parts for this engine, so I would like to share what I have uncovered with other owners of this engine and perhaps it could help you. Since there were way too many miles, missing parts, and other modifications made to this vehicle, I decided to go the route of a resto-mod, but keep the original 301 turbo as I believe it would increase the value of the car. My goal was to build a 301 turbo that can reliably make 500 hp. I'm sure everyone is rolling their eyes after reading that last sentence, and there is a good chance I will not be able to hit that goal, but I think I can come pretty close. The biggest issue is the intake and heads. I have taken out a huge amount of material from the intake, increased the size of the ports, and have heavily ported the heads. The AIR bumps in the exhaust have been removed, as well all of the casting flash, and the exhaust ports have been polished. The casting flash has been removed on the intake ports and the bowels have been cleaned up. The protrusion on the intake valve boss has been completely removed and blended into the bowel. A heavy side bias was introduced into the intake ports, so hopefully that will help flow out quite a bit. Many may argue that by make such heavy modifications that it will slow velocity down too much, but you have to remember that the ports in that engine are very small and could afford some enlarging. The valves are 1.88 intake and 1.60 exhaust and have been machined for positive oil seals. The pistons are custom Wiesco pistons with their ArmorPlating and ArmorFit coatings. The ArmorPlating electroless nickel deposit should help cool charge temperatures by at least 60-70 degrees or more, so a little more boost can be applied. The rods are forged Scat I-beam 6 inch rods. The stock rods are 6.050 inches, so the piston height was adjusted for these rods. They were also narrowed to .904 inches stock Pontiac 301 dimensions. The rods are rated for 700 hp, so the fact that they are I beam rods is not an issue. Of course, new ARP bolts complete the bottom end. The camshaft is a hydraulic roller, 226 duration at .050" lift, 540" lift with 1.65 roller rockers on a 114 degree LSA., along with new springs and roller lifters from comp cams The turbocharger is being entirely upgrade and machined for a larger turbine and billet compressor wheel and upgraded bearing, along with other upgrades, such as a billet actuator, ceramic coating, and other upgrades. I am also building a set of stainless steel tubular headers with anti-reversion cones. Each header will merge into 1 up-pipe, rather than the current setup, which is driver's side exhaust is sent to passenger's side manifold, and then that is sent using 1 up-pipe. The downpipe will be a 3 inch stainless steel pipe and branch out to 2 catalytic converters and then reduce to a pair of 2 1/2 inch mufflers.

The interesting part of this build has been the head gaskets and crankshaft. Needless to say you can't get MLS gaskets for this engine without paying Cometic $5000 for tooling and then you have to buy a minimum of 75 gaskets (I know, I checked with them). So, I had custom MLS head gaskets made for this engine. I am also in the process of having a custom 4340 billet crankshaft made that is based off of the Pontiac 301 crankshaft, but it is being changed to internal balance and will include 6 counterweights. I am having a Chinese firm make the crankshaft as I do not feel like paying $3500-$4000 for one to be made by a domestic company. Let's be real here, the domestic companies have the Chinese firms CNC the blanks and have them delivered here anyway, so why should I pay them all that money for what? Plus the crankshaft the Chinese firm that I selected is making it from a non-twist forging at a price way below what the domestic manufacturers want to charge. Given that the engine should make max power around 6200 RPM, I thought it would be a good idea to just pony up the cash for a better crankshaft. The entire engine assembly will be cryo treated as well. If anyone else is building, or wants to build a 301 turbo that will turn more than 5000 RPM, and is interested in a 4340 forged billet crankshaft that changes the balance to internal balance, but doesn't want to pay the $3500-$4000 price tag for one, let me know, or if you're interested in MLS head gaskets with a stopper layer, let me know.

Anyway, that's my build. There's a lot of other items I haven't included, such as boost control from TurboSmart that allows boost adjustment from the cockpit, as well as a nitrous system to minimize turbo lag, and the setup of Holley XFlow system, but this post would get way too long if I included everything.

If you wish to keep the 301 for future value potential, why not just store it and use an easier to find Pontiac 350, modifying the turbo to fit the intake? You'd get better heads and crank without all the work.

I think the value of the car may be higher if I could make it a serious performer by upgrading the original engine to a satisfactory level. It's well known those engines are quite weak out of the factory, so yes, it will take quite a bit to get make it a performer, but I just don't think it would be as valuable if I just dropped in an LS. That's what everyone does and I wanted to do something that stands apart from the crowd. I may be wrong and get responses that say "Hey, horsepower is horsepower and it doesn't matter how you get it as long as you have it.". In that case, yes, you're right, I would have gone through a lot of work, and expense for nothing, especially if I could have just found a junkyard LS and cheaply upgraded it. I guess I just like taking the path less beaten.

I agree on not using the LS, which is why I mentioned a Pontiac 350 instead. :) For that matter, if you want to go down the less beaten path, you could fabricate a special intake manifold for your 301 to would allow the larger valve 350/400 head to be used, they have the same bolt pattern. Do you have your new crankshaft yet? With a custom spacer (due to the narrow thrust bearing) you can use a 326-400 crank which have the same main bearings.

Fabricating an intake would have cost more than what the billet crankshaft cost me, oddly enough. I simply sent a standard Pontiac 301 crankshaft to this Chinese firm I selected and they are copying the crankshaft, but adding 4 additional counterweights. It is nearly complete and is going through testing now. The MLS gaskets were a tough pill because Cometic doesn't have that pattern on file. It really is a question of just how much power is enough. The limiting factor here is the intake and cylinder heads, but I ported the intake and heads and I believe the piston coatings will a few extra pounds of boost, not much, but perhaps enough. I think I have enough volume from the intake and the side biased that I introduced in the bowls of the intake valves may be enough to get to 500hp. I am switching the ignition to a Holley DIS, as MegaSquirt presented other challenges. The tubular headers will have a thermocouple at each port and tie in to a single pyrometer that will help to fine tune ignition timing for each cylinder. I have a local place that is cryo treating everything for just over $500, which I thought was a great deal. I think I should be able to get close to my goals and all with the original engine. Again, I just think the car would have a higher value restomoded with the original engine. If I were to put it to the side, I would have just gone to an LS and gone down that path. I may be wrong, but I guess I'll find out after I am done driving the car and put it up for sale.

It seems that you have researched your build well. Will your custom crank retain the stock stroke? And are you running an aftercooler? Any transmission mods or rear gear ratio changes?
I'll keep following this build for sure!

Yes, I am retaining the stock 3" stroke. Given the camshaft grind, the engine should make max power around 6200 rpm. I think I ported the plenum, intake, and heads with just enough volume to make it to around 6200 rpm, or at least close to it. I wanted to keep the dimensions close to the original factory specs, which is why I went with the 6" Chevy rods. I do realize that the engine would have benefited from a longer stroke and different rod to stroke ratio, but there is a point of reason where costs and build parameters have to mesh together. As far as aftercooling is concerned, the only real option is water/meth injection, which I will employ. I am going to try and create as much pressure and atomize the water as much as possible, although I haven't decided if I am going to let the EFI ECU control the injection unit or if the boost controller will do it.

As far as the driveline is concerned, my wife wants a manual transmission because she will be driving the car too, so I am going with a Tremec T56, though since the rotating assembly will be internally balanced, this will open some options as far as a flywheel is concerned. I haven't decided on the final drive ratio yet, but that will should be easy enough after the engine is dynoed and max power and rpm are verified.

A T56! Well, that overdrive will let you pick a suitably steep rear end ratio at least. What pistons are you choosing, and are you increasing the 7.6 compression ratio? Given your more modern ignition controls and water injection I would think you'd take advantage of this.

Thanks for doing something out of the ordinary with this project.

Yeah, I am thinking I will probably end up with something between 3.30-3.50, but it really depends on the Dyno results.

As far as the pistons go, I went with custom Wiseco pistons. I had the ArmorPlating and ArmorFit coatings applied to the pistons and the compression height had to be adjusted by .05" due to the shorter Chevy rods. I am hoping that between the stainless steel rings and the ArmorFit coating I will reduce blowby significantly. The ArmorPlating coating will protect the pistons against detonation and should reduce combustion temperatures by at least 70 degrees, but probably quite a bit more. All of that should allow me to run a couple more pounds of boost, maybe 2 or 3 pounds on 93 octane. I might be able to get even more boost than that with the DIS and fuel injection system, although I am not quite sure how I am going to deal with setting the ignition if I have a wide temperature variance between cylinders. I have thought about it, but the fact that the heads and intake are siamesed is giving me fits on how to deal with it. Additionally, I have to use TBI for the injection system as the housing is getting in the way of the 6/8 intake port, so I can't adjust fuel ratios for each cylinder. I have considered adding a spacer between the turbo outlet and manifold and then modifying the oil return line, but it would have to be a long spacer, which would present other challenges. I have verified that I can fit 2 injectors in each, but just barely, still though, I can do it. I think the long spacer would create too many other issues, so I have decided against it.

You are correct about the compression ratio, there is no reason to keep it at 7.6, so I am increasing it to 9. That might sound a bit high, but the engine will have modern controls, so I think I can make it work. I have toyed with the idea of individual water injection with each cylinder, but I am not quite sure how I would control that system. Going that route would certainly help with wide temperature variances between cylinders, but I am inclined to see what kind of exhaust temperatures I record first for each cylinder and then decide on how to deal with any wide variances. Who knows? Maybe I get lucky and everything is close enough not to require additional modifications. I know I shouldn't rely on just crossing my fingers, but for that issue, it's ok to take a reactive, rather than a proactive, approach.