I've been considering a 406 build recently, and came across Atilla's build in the forums. I already have a couple items pieced together, but like always it started as something else. Originally I had wanted to rebuild a set of heads for my 70 rs and after reading "The Goodwrench Quest" and saw how much a difference good heads made in power i set out to find a good set of heads for cheap. I didn't go vortec cause I was dealing with an older SBC so I found a set of '69 186 heads on craigs list and had a local machinist work em over for me ie bowl radius/gasket match, new exhaust valve seats, machined stud boss's for screw in studs and guide plates, valve grind and new valve guides. Well, since the 70 is torn down and going nowhere while doing body work etc the heads have sat on the sidelines. Then my brother decided to move back to Idaho this summer and wanted to sell me his 400 block. That's when i came across the Impersonator articles and saw what kind of numbers a bored over 400 could put out and swore that was what I wanted to do.

So my machinist has the 400 block and I've got these heads and new cam that i was going to use in the 350 and am wondering if it would be at least a decent combo for a 400 setup.

Here's attila's 400 list:

400 with dished pistons.
9.5:1 compression
coated-top pistons
COMP 12-000-8, 3017/3038, 110 cam on a small base circle
Dart Pro 1 180 cc heads
Dart dual plane air gap intake
1.5:1 roller rockers
Demon 650 carb
1/2" carb spacer
1.75" long tubes such as Hooker p.n. 2210-1HKR
note that this cam will never pass a tailpipe sniffer.


and Here's what I have (and what my machinist reccomended is marked with *):

400 bored 30 over
*KB147 pistons (4.155" w/18cc dish)
*.005 deck height (quench of .045)
*Eagle cast steel crank (only $150 on jeg's)
'68-'69 186 heads (1.94/1.5 and 66 cc according to machinist), 1.52 rockers
270h spec'd cam but with 112 center lobe angle
Edelbrock rpm intake
Edelbrock performer 1405 carb (600 cfm)
*3.42 rear
TH350 tranny/ stock torque converter
1-5/8" headers



It's plain that my list is a far cry from Atillas so I'm wondering what i should do. I mainly wanted power up to 5500ish rpm's . The rear end and tranny/converter i haven't settled on yet (i really want a stick) and I'm sure the cam and carb might fall under fire (seems more suited for a 350 engine but i'm no expert) but maybe not since the 186 heads might be the restriction here. Opinions and recommendations are welcome!

Thank you

Alan

 

Cam and carb ARE both wrong, even though the heads are gonna be a limiting factor.
You can get it to pull to 5500 rpm.
The thing is, I can't suggest a cam that'll like that and your crappy TH350. Choosing a cam would be easy if you had a 700R-4, but without that, either it'll be a dog off the line, or it'll get about 5 MPG and not pull past 5000.
You will need a 750 carb. And you now have some decisions to make.

 

ok, new carb and 700r4 which I wasn't expecting, interesting. I was going to stay automatic to keep from cutting into the floor pan, but if I want to make this "my dream car" it would ideally have a stick shift for the occasional auto-cross weekend. I heard i could put in a 2004r (did i get that right?) and wouldn't have to change the driveshaft.

Atilla, you listed a 650 carb in your original list but recommended a 750, curious to the reasoning behind it (perhaps the demon carb is that good?). I have a quadrajet lying around that i could rebuild, not sure if that qualifies as a valid 750 carb.

For the cam, what would work best with my heads? The car would mostly see the coast here but would end up in Idaho (5k'ish ft) for the autocross with the bad side of the family

If this combo is just that bad with the 186 heads and the right cam/carb can't fix then I could sell the heads to put towards a new set and shoot for your build, or just throw that stuff on the 350 like i had originally planned.

anyways, the wife needs me to help with packing for a trip so I have to go and won't be back for a few days. Thanks again for your response Atilla.

Alan

 

First, the carb: Since you choose Edelbrock, you need to know that they dry-flow their carbs to get cfm ratings, while Holley and Demon both use wet-flow. This means an Edelbrock 750 is about equal to a Holley or Demon 690, if they offered such a thing.
2004-R is good in that you can keep your driveshaft, and can use a 700R-4 shifter, but bad in that you have to fabricate a custom torque-arm mount, or switch to a Jeg's short torque arm. Or delete the torque arm the way five7kid did. Also, you have to fabricate a new rear trans mount, since it's so much farther back. I've done it, for free, but it's not entry-level stuff. You'd probably find it easier to get everything you need to do a 700R-4 from the salvage yard.
The 200-4R does have more performance-oriented ratios than either of the other 2.
Not many Q-Jets really flow 750, though all have the potential to be modified to. The Q-Jet is the best, but also the most difficult to tune. The Edelbrock is the easiest to tune, since they include instructions and offer calibration kits which include further instructions. But if you call Demon directly, you'll get a carb that won't need any tuning.
Picking a cam is the final step, after you've committed to everything else.
Since you have a 400, maybe you could sell the heads and the 350 to put towards better heads.
Driving from Washington to Idaho, you'll quickly grow to hate 3.42:1 gears without overdrive. been there, done that. And in a 400+-cube F-car which did get a 200-4R, and it loved the improved first gear, even with not-good heads and a mild cam.
So, to summarize: change the trans, decide on a carb, try to sell the 350, try to sell the heads, and report back when you've made some progress.