abadv8

Good morning,

I’m coming up on my goal of finally building an engine for my car. I bought the car 13 years ago, and said that when I got it would pull the engine and swap in a 350. Lots has changed since then…

Up until about a week ago I was dead set on a Megasquirt driven, TPI injected, 383 cid stroker. I was really hoping for about 600 hp out of this combo, but the more I add things up, the less realistic it becomes (on a reasonable budget anyway).

Enter Thirdgen.org & the “Power Adder” sub-forum. Now, I’m seriously considering a “built” 350 again. Additionally, I’m really thinking about trying for 700+ HP on a twin turbo, TPI setup... still running Megasquirt because the concept is pretty cool to me.

I’d like to touch briefly on my qualifications for such a project: I was a submarine mechanic for 4 years, I worked as a machinist for 11 years, I earned my first degree in mechanical engineering a few years back and am currently working on a second BSME, I own and can operate a TIG welder, I just finished my heated shop and have a reasonable selection of metalworking tools, I have the capability to have parts laser cut from up to .375 inch material, cars/engines/turbochargers are not foreign to me.

Now, let me disqualify myself… It has been many years since I have worked on my baby. I did not keep up with all of the changes in technology with respect to forced induction and F-bodies. I’m not quite sure where to start on this build… I have a case of project paralysis right now.

So, with that I have a few questions that I would like to bounce off of the experts:

-If I were to build a 5.7L one piece rear main engine for boost, would a forged crank, forged H-beams, and forged pistons be sufficient for 700+ HP?

-Are you guys running ARP head studs to hold the heads down?

-I’m sure I’ll get hammered for this but, eBay TT kits for the TPI… ~$1500.00… I’m sure it would need some heavy massaging, but would it work to get me started with forced induction (manifolds, I/C, charge piping, etc.)?

-Am I better off to just build everything with respect to the exhaust manifold and charge air piping myself?

-How many of you guys are building your entire setup yourselves?

-Am I completely insane?

Thanks for your time guys… it’s nice to be back in the game.

Car_2

here is my $.02... i just finished my 600+ rwhp twin turbo build.

i started my twin turbo project thinking that the most expensive parts were the turbos, wastgates, and blow off valve. I was way wrong, (but i do have expensive taste). It took me over two years to build mine and around $10+K in money by time it was all said and done. (not including engine, transmission, and rearend.) a lot of my costs were for engine management, intercooler, stainless piping, muffler, injectors, a second fuel system, air filters, silicone couplers, t-bolt clamps, tools (like a bead roller for the tubing) flanges, solar flux, filler rod, shielding gas, files, grinding wheels, gaskets, stainless hoses, A N fittings, brackets, alternator, power steering pump, belts, turbo insulators, coatings, hood insulation, motor plate, mid plate, wire insulation, spark plugs, plug wires, v-band clamps, fuel pressure regulators, boost guage, afr guage, fittings, dyno time, ect, ect, you get my point.

then you need to build up the driveline to handle that kind of torque, upgrading the clutch and transmission, (or converter and auto trans) and rearend.

the engine, like you said will need forged internals (if you want it to last in that power range). Yes, with head studs, and i used a different material exhaust valves. (can remember the name of them). custom cam ect, ect.

then when you get all that done and running, and you have a big grin on your face on how fast it is, you realize you need to upgrade the tires because you have no traction, after that you find out how bad the brakes on a third gen are, and you need to upgrade those too.

but after all the work, and money spent, let me tell you it feels really good to have a third gen that runs as fast or faster than a new zr1 vette. It may not turn or stop as fast, but it feels really good for less than half the price.

and again, i have expensive taste, a lot of guys will do it cheaper and be just fine. this has been my experience.

it was a lot of fun to build, and drive! cant wait to get it to the drag strip and see what it does!

ZZ3Astro

Sounds to me like you're in a lot better shape than I was when I put together my single turbo TPI. You've got a heated shop and access to a laser cutter, plus it seems you have the budget worked out for a nice build on the engine.

The ebay stuff is cheap enough that you can replace the individual parts with better stuff as you go. If you're planning to keep the car in fairly stock condition (keeping stock hood & most accessories) you won't find a lot of help with the turbo kits available on ebay. If you're just going for cheap speed, you can make one of the ebay TT setups work with some reinforcing of known weak areas well documented on these forums. Also consider the single turbo route, which makes it quite a bit easier to keep accessories such as AC.

You can support 700 hp no problem on a single.. some would say you need at least a 4 inch downpipe and others believe a 3 inch will do it. Either way you can use oval 4" and snake it down the passenger side of the engine without much problem. I prefer using the minimalist method of getting as much as possible from as little as possible.

I would probably lean towards piecing together what you need vs a complete ebay kit. A lot of decisions will need to be made with things like routing the intercooler piping and various couplers, V band clamps etc. If you buy a kit, you're stuck with either using what they give you or spending more money on the parts you really needed. That said, I've had great success with my ebay turbo and BOV. My intercooler is the same as what you can get on ebay as well as the intercooling piping and most of the couplers. I just ordered everything to my requirements and as I needed it.

Good luck on the project, to me it sounds like you're capable of putting something really nice together and I look forward to seeing your build progress.

abadv8

Guys, thank you so much for the insightful responses.

I can definitely appreciate the expensive taste perspective. I like to spend my money on things that I can use to build other things, so I really am pretty well outfitted. In addition, I am fortunate enough to hold a position with a company that works in almost exclusively stainless fabrication. A great deal of the work we do is with sanitary stainless tubing, so I believe the charge air piping and exhaust should be top notch.


Looking at the degree of difficulty of the work that some people here have done, I am not worried at all. What worries me is that I have had this car for a long time (relatively speaking) and there is a lot of sentimental value there. So, I am a little apprehensive about chopping it up.

Fabrication has always been a serious interest of mine, and I have always wanted to try building a set of headers, and this looks like it might be worth a shot. I can certainly draw up a set of flanges and have them cut out of stainless. I know that running .250" material is preferable, but I could make them thicker if needed. How thick would my flanges need to be? What diameters are people running for primaries? Is 1-5/8" the norm?

I did seriously entertain the idea of a single turbo setup, but thought that the twins would make it easier to retain the accessories. I guess it's been a while since I've peered under the hood...