4.3 Supercharged Chevy

[Qingdao]

Finally got my hands on a cheapo boxster. Its a pile LOL, BUT $1500 seemed about right for a strait chassis and clean title.

Now I just have to wait for the half off weekend at LKQ. I am gonna shove a 4th gen 4.3 Chevy engine in this thing with an Eaton M90 blower.

I think I'm gonna draw through an edelbrock, but I might go with a Holley. Haven't decided yet.

At anyrate, I got this thing, but now I have to go on vacation... Sucks cause I'm going to be off with the wife and not at home in my garage. :lol:



Well here is the pile... (yes I do body work too)

[Qingdao]

Didn't take long. Got a nice cheapo Eaton M90.

$100 and after I get back from vacation I can get a rebuilt snout from Ebay for $300.

Rebuilt blower for $400 not too shabby.

[78F350]

Looks like a cool project. Lots of the guys on the forum wouldn't touch a $1,500 Boxster, but at that price you've got nothing to lose and a lot of potential fun if you like playing with cars. I'm looking forward to the progress.

[Qingdao]

Originally Posted by 78F350

Looks like a cool project. Lots of the guys on the forum wouldn't touch a $1,500 Boxster, but at that price you've got nothing to lose and a lot of potential fun if you like playing with cars. I'm looking forward to the progress.

2 years ago I wouldn't have either. My wife had an auto and that thing was super fun even though slower than a heard of turtles. That car's gone now its my turn.


Got a bit of inspiration off of YouTube. This guy went ham with the intercoolers. I don't think I'm gonna have to use two belts, but who knows at this point.

https://www.youtube.com/watch?v=L_FRdIjGkgg

^^^ Apparently I'm not the only idiot who wants roots noises emitting from their V6 engine.

[78F350]

I had an M90 that I thought about blowing down into a VW VR6 with. After laying it out and looking at what it would take to do right, I passed the whole project on to someone else.



Do the M90s have a stock mounting on the 4.3, or do you have to fabricate it?

[Qingdao]

100% gonna have to fab.

I was gonna just do a piece of 1/2" aluminium. Tap some holes in the top to bolt the eaton to it and bolt the bottom to match the 4.3 intake. That'll also give the ability to position the snout where I want it in-between the alternator and A/C compressor.


Accessory position is the reason why I've chosen the 96-02 chevy 4.3. The accessories on the 4.3 almost line up perfect with the accessories on the German H6 engines. So all I have to do is break out my line lock crimp tool and fab up some hoses. (that's a big fingers crossed there LOL)



As for engine building I am just going to put a healthy cam in it and some good pistons and rods. Maybe some light weight rockers for show. Nothing too spectacular; I just want about 300whp maybe 350 if I'm lucky. BUT the torque should be to die for.



One question I'm wrestling with is weather or not to buy new springs. I like the stock ride height but I don't know how much the original springs have sagged over the 20 years of life. Especially since this thing has like original struts on it (its a motor boat) so I'm sure these springs might be "sprung out". Just don't know if its worth the cash to toss in some new oem springs.

[itsnotanova]

I love engine swaps so don't take this wrong, but won't you have a huge issue with how tall the motor is? Let alone with a blower on top

[Qingdao]

Originally Posted by itsnotanova

I love engine swaps so don't take this wrong, but won't you have a huge issue with how tall the motor is? Let alone with a blower on top

I hope so. I'm gonna build a plexiglass top. I wanna see this...thing.


I do want to do the "cayman style" hard top as well. So I don't need room for the convertible top. That whole rear trunk area is probably going to be substituted by a series of square tubing supports.

If the blower, carb yada yada are to far aft/high and I can't close the rear trunk; I might turn a pair of elbows around 120* go with a pair of SU carbs on top of the valve covers. One conveniently placed in front of each of the side intakes.

[robdelorenzo]

“I love engine swaps so don't take this wrong, but won't you have a huge issue with how tall the motor is? Let alone with a blower on top

I hope so. I'm gonna build a plexiglass top. I wanna see this...thing.”

This line had me howling
Gotta love the enthusiasm and creativity on this forum.

There are so many people that know these cars well on here that it’s not even always about budget or $$

Anything is possible with a little imagination.
Well done, enjoy the car!

[Qingdao]

Well that cross member isn't as strong as I remembered when I took it out. Its quite thin if you don't know. So I made it stronger as it is going to support an engine that weighs almost 500#s. This is just tacked on for the moment (ran out of wire feed and I don't like my skills with my arc), but the bolt holes match up.

[Qingdao]

Welded my little triangles in there.

God help me I kinda like the red paint. lol

[99Roadster]

Respect your initiative for taking on this project.....Whatever you do just keep us informed of your progress if you would please.....And good luck!

[Qingdao]

Originally Posted by 99Roadster

Respect your initiative for taking on this project.....Whatever you do just keep us informed of your progress if you would please.....And good luck!

Well I'm trapped in a forced vacation with my wife ATM. I'm so glad to be getting back to the garage in the next few days. Then I can start mocking things up, and poking the car.


I think I am just gonna buy a $125 4.3 off ebay for starters and toss a cam in it. Not even gonna upgrade rods.

I got the blower, and I found a used eddy on ebay as well for $100. Manual choke


Honestly, for the growing crowd of IMS failure guys. I think the 4.3 is the way to go. Naturally asperated and carbed; you won't have to worry about wiring (there are electric chokes but I like to pull the nob). Its 4" shorter than an LS motor so you won't have to cut up the firewall. With a simple cam and an intake you've got almost 300#s of tourque which is more than the 3.4 Porsche engine. And they are CHEAP and plentiful; Kennedy adaptor and a bit of angle iron added to an engine/cam/carb/intake is less than a 3.4 Porsche engine.

[JayG]

Originally Posted by Qingdao

growing crowd of IMS failure guys. .

really ??????

[Qingdao]

I took a crack at trying to replicate a part out of foam.


I put my M90 in a bag....



Then I covered it with great stuff...



Then I took the M90 out of the bag...



Then I filled that void with great stuff and Styrofoam...



The end result...




I took the end result out of the plug way too soon because I noticed the great stuff wasn't curing on the outer edges of the plug. I tried to drill an air hole and the bit caught the bad and made a royal mess....

I think I am on the right track but I need to use a card board box to retain the negative. I should be on my way to scoop up a 4.3 tomorrow.

[Qingdao]

Well... to hell with making a foam copy. This thing is gonna fit no problem. I might have to hack the fire wall some, but not any more than you'd expect.

And OoooHMYgod does the Eaton sit perfect on top of the 4.3.








All I should have to do is hack down the back of the M90 just a hair and tig up a square bore plate. Adapt the M90 for the 4.3 LIM; drop the carb on it and call it a day.




As for the size constraints here is the skinny...




The 4.3 is 22" long from flex plate to W/P... The 2.5 Porsche is about 23 ish (I can't exactly see down in there).

The 4.3 is TALL from the bell housing up its gonna be a whopper of 12" and after about 5 inches forward of the bell housing its gonna be about 16" (cause of the carb). According to my rough estimates that puts me at about right at where the top of the rear storage bin would be. Another words this is gonna fit under the glass.... BUT JUST barely under the glass.

[bcrdukes]

I'm curious about that motorcycle you got in that last photo

[Qingdao]

Originally Posted by bcrdukes

I'm curious about that motorcycle you got in that last photo

She's my long time compatriot. A 1974 CB550. I used to do all kinds of buying and selling of motorcycles, you know "fliping". Don't find myself doing that anymore, but this bike has stayed around. Its the best bike I've ever had; just the best all around.







Finished hard mounting the cherrybombs to the trans cradle. Seems so weird not to hang an exhaust but the engine/trans move as one unit so does the exhaust.







And I started on my heater core return hard lines. As seen in red.

[Qingdao]

Heater core hardlines made up. They mate up to the Porsche soft lines.











I'm really stoked at how well and fast this is going. Not much more but to route the coolant outlet to the Porsche outlet. Then rebuild the engine/clean everything up, and turn the key.

THEN on to "stage II". I gotta rebuild like everything else... ugg. But that's just spending money on suspension/tires no real hard work.

[Qingdao]

Started with my adaptor plate.






And simply drill holes.








And then mockup, just for fun... cause I can't take it anymore.