Most basic turbo combo...
 

Let's assume well built bottom end. 400ci - 463.



Iron heads and have longevity.


Flat tappet or roller?
What cam specs?



How much power / boost?

400 ci 3.75 stroke is better
flat or roller will work 230-240 .050

8 psi hp somewhere around 700-750

70 Bird and myself have had good luck with a summit 2802 cam in a 455, I did have the first one get a flat lobe, but once I upgraded my valve springs, seems ok now, but dont have many miles on it, and on the second one I used the Comp cams lifters with the tiny oil feed hole on the bottom of the lifter.

What about with 265 cfm Iron d-ports @ 8.5-1 on a 406?

If you do some searches on PY you would find that Marty Palbykin's 406 engine had a very conservative 260 cfm type cast iron head and he was able to make 1600 hp and run 6.96 and 206 mph. Your projected 8.5 compression ratio will be fine.
Marty was running on alcohol so his compression ratio was closer to 10 to 1. Easy 1000 hp with the right turbo(s) for you at lower boost levels.

Tom V.

Im thinking what Charlie said sounds pretty close. I would limit the boost because of the factory block.....GO Boom, Boom! :)
Its easy to make power BUT its harder to keep it together!!

GTO George

Are you building something?

Charlie made over 700 HP with 4 cylinders and 200 cubic inches of displacement. This was factory cast iron block parts upgraded to be stronger. Lower boost and proper machining and a street/strip pontiac block around 3.75 stroke
should be fine. Charlie also ran factory 4 cylinder cranks but at much higher boost levels vs what we are talking about here.

Tom V.

I recommend that he not use a factory block with a power adder that’s making 750 or more HP. The cost of a broken engine out ways the price of an aftermarket block and good rods. It’s like Mr. Goodwrench use to say......”Pay me now or Pay me later”!


GTO George

Luhn Performance made 863 HP HP at 5300 rpm driving a belt driven supercharger at 13.5 psi of boost. The main caps were moving on the block, Fretting, and was apparent on teardown.
With a Turbo that combination could have been over 900 HP easily at 13 psi of boost.

Very easy to make the power. Much harder to keep the boost down so that the block will survive. But it has been done by different people on the street.

If you can afford it buy a good block and good crank, rods, and pistons.

Tom V.

When Marty ran his 406 cid engine, the only block out there was a original Dick Duclow block and Dick only had 50 made.
Marty stayed with a stock 67 400 block with mods. It lasted 3 years at 40+ psi of boost. All factory blocks will fail under boost at some point. Just like stock Ford and Chevy blocks do.

Tom V.

^^^^^^ what I said.....its your money not someone elses!


GTO George

Then why did you have to say it in multiple posts except to get your post count up.

The people are going to do what THEY want to do, not what George wants them to do.

Tom V.

Trying to stir up the chit in the boost forum too George?

Just giving my opinion. I've run stock blocks and different aftermarket blocks with different power adders combinations. I've also shelled out the money to fix the breakage, so when i give an opinion I understand the money cost........been there done that. Its always cheaper to do it right the first time!!
NOW............if you're only going to run 4,5,6,7 lbs of boost and play with it on the street once in a while............then a stock block with GOOD rods will work!

GTO George

As somebody that's not a racer, but is interested in turbocharging, it's helpful to see the side that says, do it right the first time with an aftermarket block, high end rotating assembly etc. However we also need to look at the basics too, which is what was being asked about here.

I also need to know what the limitations are of different types of configurations.

stock block/stock rotating assemblies
stock block/aftermarket rotating assemblies

etc.

What a lot of people forget is not everyone that wants to try hotroding something like this, has 15-20K to spend on just an engine.

My setup is a 455 with an N crank, prepped factory rods, Speed Pro pistons and a set of as cast KRE D ports at around 10.2:1 compression. I "think" this setup could work well with e85 and mild boost in the 8psi range. But if I ask that, instead of talking about the technical aspects of that plausibility, the default for most is just to say don't do it, go spend a lot of money on an aftermarket block, rotating assembly, heads etc.

I would say stock block is fine . As for a stock prepped factory rods and none forged pistons, I would say no way . Stock cast crank , yes its ok . 10 to 1 fine with e8 but not optimal but will work.. The stock rods in my mind would scare me. Thats why i say no. But try it if you feel different . Id like to know if im wrong for sure...

The only thing I will say about the 455 combo, is get a set of better rods. Eagles are cheap and will handle a lot of power.
I have had a stock block for a long time. The stuff I broke had nothing to do with the block. I add the 3 billet center caps, forged eagle crank and good rods. 8 psi gets me about 700-750 h.p. Plenty for the street and with the proper tune will run a very very long time. 12 PSI on the street and hang on, you go for a ride with the car trying to peel the tires off the rims.
Turbos are easier on parts than high compression and nitrous.
No reason to be worried about a stock block if you know it's limits.

I would not be afraid of putting 1000 hp to a stock V8 block with a turbo. My 4cyl block has been living with 800hp which is 200 hp per cylinder . Now think of it this way. theres alot more force going though and and against the cylinder wall with 200 hp per cylinder then 100 per cylinder right? So 800hp being produced from a 8 cylinder is nothing compared to whats going on with 800hp on a 4 cylinder.. So why wouldnt it live with 1000hp ?

i agree 100% but boost can be addictive that 5-8 lbs of boost can turn into 10-15! :)
With only 5-8 lbs of boost stock block would work with good rods and forged pistons.

GTO George

Absolutely agree on the slippery slope. I've had boosted (actually have currently, but that's just a modern daily) cars in the past and the want for more more more is always there.

Hey Ponjohn are you building something ??