building a 406

[Sandmann]

I have to agree with Gitdowns.
Don't listen to those guys on Horsepower TV or in CHP magazine. They are paid to advertise parts. Nothing else. It's as simple as that.

If you are building the engine for 400 hp or so, and throw a 150 shot on it, most of the stock parts will live a long time. Just remember that when the time comes that you want to go faster, a better crank and rods will be needed. A factory 400 block is good for 550-650 hp or so. It doesn't matter if it has splayed caps installed and plugged deck and steam holes, 550-650hp seems to be the "safe" limit. That being said, I have seen guys pushing over 900 hp with nitrous using factory 400 blocks. But most of them will tell you that they are really pushing their luck.

With the short block, step 1 is to disassemble the engine to see what you have to work with. Depending on the condition of things, you might be able to just replace main and rod bearings, break the glaze on the cylinders for the new pistons and rings, and install a new oil pump. If the cylinders must be bored, honing with a torque plate isn't necessary for what you are doing. Having the rods rebuilt with good bolts would be a good idea and worth the money. I wouldn't put any extra money into the block. Stay away from splayed caps, you don't need them. Yes, longer connecting rods are always better, but with your goals and budget, don't worry about it.

Forged pistons are great, but hypereutectics are fine for what you are doing. A good friend of mine has been spraying a 383 with hyper pistons with a 250 shot for years now. I was convinced he would burn up those pistons, but he hasn't after 7-8 years now. It's a street car that he often drives to work. He has never had any problems with it.

Don't worry about balancing unless you are going to spin it past 6000 rpm a lot. Running it up to 6500 once in a while will not hurt anything. And I can tell you from experience that with heads under 200cc, 5500-6000 rpm is probably all you will get out of the engine.

As for the upper half of the engine, vortec heads would make for a great, torquey street engine. I would run a flat tappet cam with duration in the 235-245 at .050 range and as much lift as the pistons and heads will allow.
A single plane intake will generally work better than a dual plane on your 400, but if I already had a dual plane, I wouldn't hesitate to use it.
A basic 750 cfm carb is all you need. Carter carbs are great for street cars.
A stock balancer, flexplate, distributer are all fine.
1 3/4 headers might be beneficial, but I can't remember what those vortec heads flow on the exhaust side.

Anyway, thats what I would do if I were in your shoes, but this is just my opinion!

Have to agree. Unless you are going ultra gonzo hi-po you don't need all the super high buck stuff to have a quick ride. Its hard to do at times but my motto is to try not to use the credit card and stay outta the machine shop as much as possible.

 

[PRO 48 Fleetline]

Great thread and always like slimbos input very informative input.
Ive built my 406 a lil at a time and i think pretty afordable.

1970 406 arp studs
3.75 Scat crank internally balanced
6" Scat i beams with clevites
11.1 Mahle forged flat tops with 2 valve releifs
Melling select pump and bolt on pick up
7" quart pan with kick outs and trap door
Lunati VooDoo solid roller 242-249 @.050 585"
stefs oil restickters
Hurricane ported intake 750 mighty Demon
1" 4 hole HVH
210 Po-Filer 64 cc 2.05 1.60 with 1.5 lunati's
MSD billet ignition with a 6AL and ss msd coil
Cloyes true billet double roller
CSR electric pump
SFI Dampner with TCI flywheel

 

[Sandmann]

What did you decide to go with?

 

[slimbo]

Great thread and always like slimbos input very informative input.
Ive built my 406 a lil at a time and i think pretty afordable.

1970 406 arp studs
3.75 Scat crank internally balanced
6" Scat i beams with clevites
11.1 Mahle forged flat tops with 2 valve releifs
Melling select pump and bolt on pick up
7" quart pan with kick outs and trap door
Lunati VooDoo solid roller 242-249 @.050 585"
stefs oil restickters
Hurricane ported intake 750 mighty Demon
1" 4 hole HVH
210 Po-Filer 64 cc 2.05 1.60 with 1.5 lunati's
MSD billet ignition with a 6AL and ss msd coil
Cloyes true billet double roller
CSR electric pump
SFI Dampner with TCI flywheel

My input was spot on for thats guys post....... Dont worry about balancing....No need to use a torque plate when honing......No need to cut the crank....Just a hone and new bearing and spraying 150 with hyper pistons is acceptable? Yes i hate the internet sometimes ](*,)

 

[tiedyemike8]

Maybe I was misleading in my post.

xtremeclonedss stated that he had a budget of $2000, it's mainly a street car but may race it in a few years, might spray it with no more than a 150 shot, and only drives the car a couple times a month to car shows.

Given that information, I stand by every word of my post, but admit that I should have elaborated more. A mild engine under 450hp, that is hardly ever driven on the street OR the track will live a long time with the parts I listed. I also stated that when the time comes when he wants to go faster, different parts are in order (I just said crank and rods, but should have included that a different level of machine work and better pistons would also be required). I have seen quite a few engines come apart looking like new that were still within factory spec. When that is the case, there is nothing wrong with reusing the parts for a mild performance build.

I obviously should have added that I would never recommend an engine like I described for regular drag racing use. But to keep his budget, and considering he wont race it for at least a few years, the combo I listed would make for a very fun street car that will live many miles on the street. And it would easily survive the drive to a couple car shows a month, and even a pass at the track with a 150 shot once in a while.

 

[Supe]

Stock block, pink rods, TRW's, factory crank, good bolts, out of the box 230 Iron Eagles with a big solid roller cam. Ran 7.20's with a broken distributor hold down pig rich first time out. Timing ended up being waaaaaaaaaaaaaaaay advanced. Easy 6 second motor without even trying. Spun it to 7400 every time. Block cracked, bottom end was fine.

 

[slimbo]

Maybe I was misleading in my post.

xtremeclonedss stated that he had a budget of $2000, it's mainly a street car but may race it in a few years, might spray it with no more than a 150 shot, and only drives the car a couple times a month to car shows.

Given that information, I stand by every word of my post, but admit that I should have elaborated more. A mild engine under 450hp, that is hardly ever driven on the street OR the track will live a long time with the parts I listed. I also stated that when the time comes when he wants to go faster, different parts are in order (I just said crank and rods, but should have included that a different level of machine work and better pistons would also be required). I have seen quite a few engines come apart looking like new that were still within factory spec. When that is the case, there is nothing wrong with reusing the parts for a mild performance build.

I obviously should have added that I would never recommend an engine like I described for regular drag racing use. But to keep his budget, and considering he wont race it for at least a few years, the combo I listed would make for a very fun street car that will live many miles on the street. And it would easily survive the drive to a couple car shows a month, and even a pass at the track with a 150 shot once in a while.

if you put it that way you are likely correct...but who builds something like that unless the plan to drive it with enthusiasm or take it to the track? My stock block 406 with splayed main caps and a forged crank and rods was still going strong after three seasons of racing and street driving and was in such good shape i sold it to another member instead of riping the rotator out of it for my new build. would i trust it with a 150 shot even with the good stuff in it???? id have to say no and thats why i went to a little m block this time. because when things start to wrong whether its the block breaking or a rod or whatever.. most of the time it takes some other stuff with it and i didnt want to chance that.

 

[PRO 48 Fleetline]

Maybe I was misleading in my post.

xtremeclonedss stated that he had a budget of $2000, it's mainly a street car but may race it in a few years, might spray it with no more than a 150 shot, and only drives the car a couple times a month to car shows.

Given that information, I stand by every word of my post, but admit that I should have elaborated more. A mild engine under 450hp, that is hardly ever driven on the street OR the track will live a long time with the parts I listed. I also stated that when the time comes when he wants to go faster, different parts are in order (I just said crank and rods, but should have included that a different level of machine work and better pistons would also be required). I have seen quite a few engines come apart looking like new that were still within factory spec. When that is the case, there is nothing wrong with reusing the parts for a mild performance build.

I obviously should have added that I would never recommend an engine like I described for regular drag racing use. But to keep his budget, and considering he wont race it for at least a few years, the combo I listed would make for a very fun street car that will live many miles on the street. And it would easily survive the drive to a couple car shows a month, and even a pass at the track with a 150 shot once in a while.

if you put it that way you are likely correct...but who builds something like that unless the plan to drive it with enthusiasm or take it to the track? My stock block 406 with splayed main caps and a forged crank and rods was still going strong after three seasons of racing and street driving and was in such good shape i sold it to another member instead of riping the rotator out of it for my new build. would i trust it with a 150 shot even with the good stuff in it???? id have to say no and thats why i went to a little m block this time. because when things start to wrong whether its the block breaking or a rod or whatever.. most of the time it takes some other stuff with it and i didnt want to chance that.

Yep what he said!

 

[tiedyemike8]

if you put it that way you are likely correct...but who builds something like that unless the plan to drive it with enthusiasm or take it to the track? My stock block 406 with splayed main caps and a forged crank and rods was still going strong after three seasons of racing and street driving and was in such good shape i sold it to another member instead of riping the rotator out of it for my new build. would i trust it with a 150 shot even with the good stuff in it???? id have to say no and thats why i went to a little m block this time. because when things start to wrong whether its the block breaking or a rod or whatever.. most of the time it takes some other stuff with it and i didnt want to chance that.

I have to disagree about the 150 shot. In my experience, they arent that hard on things if you are only spraying once in a while. However, as a driver, I tend to be more gentle on things than some people. A different driver may have very different experiences than myself with just a 150 shot.
I do see where you are coming from, though. You have a " do it right the first time" approach which is hard to argue with. I am generally the same way. But, the guy asked what he could build for $2000, and I still stand by my opinion.

I get the feeling that you are trying to say that he would be better off saving his money until he could afford to build a more durable engine. Is that right?

 

[JP86SS]

I get the feeling that you are trying to say that he would be better off saving his money until he could afford to build a more durable engine. Is that right?

I would think everyone would like to do that but circumstances never allow it.
I want a forged crank but... may have to settle for less to get it done in some kind of near time frame.
Don't like the idea but otherwise I may just be collecting parts in the garage rusting for two years.
At some point you need to take some chances. That is the intent of this thread to find what really can be tolerated (by real world experience)
Certainly would not be the "way to go" but it has to be the way it will be.