Ok I just picked up a 400 block with 4 bolt mains to replace my 305

Im excited for this project, I know how to do some stuff and I can figure out alot of things but I need your guy's help, I dont know enough about engine building for what I want to do.

Ok, Im going to have the block preped
And stroke it to 421 using a 3.875 eagle crank
Im going to be using Je pistions,

I want the engine to produce around 500 hp, and be as streetable as possible, I also want to hit with Nitrous at the track, about a 200 shot.

What kind of Head/Cam/Intake combos would you guys suggest?
What do I need to do to prep the block?

Thank you for all replys.

 

I can't really comment about the cam or heads etc.

But a set of SD421 emblems off an old Pontiac would look great

 

ya that would be cool lol

 

I would suggest that 3.875 stroke and a 200 shot are more than you want to ask of a factory 4-bolt block.

Go get a Motown block if you want to hang out in that playground. A factory 4-bolt block should be limited to tamer duty, like 5500 or less RPMs, more the 400-450 HP, NA-only crowd.

 

I kinda want people to think its a 350

 

I mean could it be done, or am I wasting my time with the Gm block

 

The Motown block will look just like a factory block. http://www.worldcastings.com/docs/wcatalog04.pdf , page 10 if it loads the same way for you as it did for me.

What you said could be done with a factory 400 block, the only question is how long it would last.

The answer is most likely, "Not very long."

When the factory block gives out on you, the $1900 for the Motown block will start to look like money you wish you would have spent.

 

well either way, what combinations do you think I should use.

i Have to decide weather to use that aftermarket block now.

 

I've never been good at putting combo's togther, but for an engine like that, I'd suggest all forged internals, like the crank, rods, pistons, and ARP bolts everywhere. To keep it pump gas friendly, I'd keep the compression ratio around 9.5:1 or so as well.

 

You need to decide if you want a 500 HP 421, or a 421 that you can hit with a 200 shot. Most likely, they will not be the same engine. Certainly a streetable 500 HP 421 would be the most difficult to achieve.

Most likely, AFR heads will be the hot ticket. Cam selection is best accomplished by calling the major manufacturer's help lines and telling them what you're doing. They need specifics, though, and any wishy-washiness on your part will reduce the useablility of the advice received. N2O or not is a key part of the equation. You don't build a high-horsepower engine and decide to spray it later. You build the engine for the spray up front.

 

I am positive I want to spray it. I know it will make it harder to reach my goals because I have to lower the compression.

Im not building the engine in 1 day its on a stand Imma do it right I just need the help.

 

If you already have the block and plan to use it, I'd do the following:

1) Do a street fill (about half) with Hard Blok water jacket filler.

2) Take a die grinder and polish the area around the main webbing to eliminate stress risers.

3) Install ARP main studs

4) Use Moroso deck plugs before decking the block

5) Use ARP head studs

6) Do the usual high performance machining and prep.

7) Say a prayer before you spray it.

 

lol, thanx

 

https://www.thirdgen.org/techbb2/sho...5&pagenumber=1

 

http://store.summitracing.com/partde...=BRO%2D9991000