Building my 406

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Building my 406

Postby spyderhunter » Mon Jun 25, 2018 8:23 pm

Ok, my 400 turned out to be a 406. :th: I tore it down to replace the gaskets because they leaked quite a bit, and I wanted to pretty it up a bit with some shiny parts. Got the history on the engine from the guy who built it in the mid 90s. The oil was so sludgy that I decided to look at the bearings and although they seemed decent we all know if you're that deep into it, then it's time to replace and rebuild it (unless you like taking things back apart just for fun) :bang:. I had bought a Comp Cams S12-238-2 Xtreme Energy 262H Hydraulic Flat tappet cam to use with the stock heads because I was told years ago by someone here that it was a good way to go. My question is, Has anyone used the NKB 200cc Aluminum heads? Would these heads wake it up some more, or make it worse if the cam is too small for the heads? 68cc str, plug w/200cc runners, 202/160 stainless valves. I'm not looking to turn it up much beyond 5000rpms. or set the road on fire and transport through time either, but would like it to be responsive and still decent to drive while still getting decent mileage :lol: :lol: if possible. The engine has an rv cam in it now, and this one I think is just a bit bigger than that. I am planning on using the Saginaw 4 spd with it, but have looked at the 200r4 from Monster trans. also (Shifting is for young guys)Plus I might want both hands on the wheel!!. I will eventually upgrade to 5 lug 15 or 16 inch tires, but for now I will have to stick with 13's. Not sure of my gear ratio yet. What do you guys think?
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Re: Building my 406

Postby cosvega76 » Tue Jun 26, 2018 9:26 am

That cam is a bit small for those heads - it may not be optimized, but it will still run. A 406 will have a ton of torque anyway. Even stock gears won't be a problem.

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Re: Building my 406

Postby spyderhunter » Wed Jun 27, 2018 4:53 pm

Yeah, that cam is pretty mild but with stock heads it should be ok? Just checked and I have 2:29 gears ( kinda high, but as you say, it's a torquey engine; Thinking about a limited slip to help with traction also. Would you choose the 4 spd, or switch to the 200r4? Do you think the saginaw will hold up?
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Re: Building my 406

Postby cosvega76 » Thu Jun 28, 2018 10:14 am

I'm running a 355 with Sportsman 200cc heads and an old Comp 268H cam. It runs fine. Your 2.29 gear will be okay if you run the 13" wheels, but don't expect any traction. That will be okay, though, while running the Saginaw. It may not hold up if it hooks, though. I'm running a 200-4R and I like it.


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Re: Building my 406

Postby 75Monz » Thu Jun 28, 2018 11:31 am

I am planning a similar setup for my 75 TC. Trying to decide leaving it a TH350 or use the Saginaw. I've got the 2.29 gears also, open diff. Planning on bumping it up to 3.08's with 15" wheels and a truetrac with 295/50's wedged in. I'm having serious doubts about how long the saginaw will last with this combo, just remembering back to my 71 vega gt with a mild 400hp DZ302, open diff and 2.92's on 13's I think. If I ended up wheel hopping, mostly split the case every time unless I got out of it quick. I redlined at 7500 before shifting, was pretty brutal, but as long as I didn't get wheel hop I could run a 12.4.
Some people are like slinkies. They serve absolutely no useful purpose, but still put a smile on your face when pushed down a flight of stairs.
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Re: Building my 406

Postby avewhtboy » Thu Jun 28, 2018 11:38 am

I am in the process of rebuilding my 413 (400 60 over)

Before the rebuild I am doing now I had installed Summit racing 1107 camshaft and a set of mildly ported cast iron Vortec heads.
I was pretty happy with the way it ran. The cam was not too big at all so now I have purchased Summit racing 1108 cam for the current upgrade.

I am also installing new pistons to bump compression up to closer to 10.5: 1
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Re: Building my 406

Postby spyderhunter » Thu Jun 28, 2018 4:39 pm

Yeah, I'm trying to stay somewhat practical this time around. When I was younger I would have been givin it all I could.... but still trying to have some fun without breaking the bank and the car. Easy to say now, but once I get to drive it, it's hard to say what will happen next. It's been almost 30 yrs since I have driven a Monza so I can't wait to get this thing back together. 7 yrs. in the garage since i bought it. Once I get started on the rebuild I will start an updated post on the progress. I'm also looking at a limited slip for the rear to help with traction and Moser axles for the 5 lug upgrade. You think the case will hold up if I'm not too hard on it? Or am I better off spinning and not splitting.... :rolleyes: Not saying I won't get on it sometimes, but hopefully not too hard; I guess time will tell.... I can't promise anything if I want to be honest about it.
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Re: Building my 406

Postby spyderhunter » Tue Jul 03, 2018 12:02 pm

I took the block and crank in to the machine shop today to get them magnafluxed and checked for any issues. They were a couple spots on the crank but I don’t know if they will need to be turned or not. Should have it back by Friday. Can’t wait to start reassembling something finally.
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