ok this summer im getting a bunch of jobs and i want to build a killer motor to put in next winter. i want around 500 naturally asperated hp. im not sure if i should build a 383 or a 400. i would put forged crank, forged rods, and flat top pistons. im definetly not an expert at this so im not sure how much hp this could hold. if i was to use billet main caps would this help with stength? my internal parts would probrably be: Eagle H-beam 4340 rods, Eagle 4340 crankshaft. i would probrably want to put nitrous system on. with nitrous id like to achive 600 hp at least. my question would be; will the block hold together with around 600hp? or should i get like a world block? BTW dont make fun of me.. im a newbie:crazy:

why not just go for the extra cubes.

The 4-bolt blocks (part# 3951511) can safely hold up to around 400-425 horsepower with excellent reliability. Sure, guys have gotten way more horsepower out of them, but they can be a liability if you're really pushing it hard with lots of nitrous. In most small blocks, having a 4-bolt main is a very good thing, but in the 400 motor, it's not as great as it appears. Ironically, these blocks are weaker in the main webs than their 2-bolt counterparts (part#s 3951509 and 330817). If you can, find one of these blocks and replace the main bolts with studs. You don't need to convert one of these blocks to 4-bolt unless you want to spend money doing something unnecessary. Remember, it's a street motor. Keep this in mind when chosing a cam, heads, and carb because this is where most guys think that bigger is better. In a race motor, maybe, but the wrong combo in a street engine will turn it into a unhappy, tempermental pig. I would suggest finding a complete 400 engine. Rebuild the bottom end with all the original parts as long as the rods and crank are machinable. Run a set of -21deg dished flat tops and top it off with a set of modified Vortec heads, a Lunati Voodoo cam, an Edelbrock RPM Air Gap, and a 750 Holley. You'll get 425 horsepower all day long and it'll be super reliable. You could make it a daily driver as long as you don't mind buying tires every few weeks from the killer burnouts that this torquey motor will produce. And best of all, it'll be easy on your budget. You could save money that could be used in other places on the car.

The 4-bolt blocks (part# 3951511) can safely hold up to around 400-425 horsepower with excellent reliability. Sure, guys have gotten way more horsepower out of them, but they can be a liability if you're really pushing it hard with lots of nitrous. In most small blocks, having a 4-bolt main is a very good thing, but in the 400 motor, it's not as great as it appears. Ironically, these blocks are weaker in the main webs than their 2-bolt counterparts (part#s 3951509 and 330817). If you can, find one of these blocks and replace the main bolts with studs. You don't need to convert one of these blocks to 4-bolt unless you want to spend money doing something unnecessary. Remember, it's a street motor. Keep this in mind when chosing a cam, heads, and carb because this is where most guys think that bigger is better. In a race motor, maybe, but the wrong combo in a street engine will turn it into a unhappy, tempermental pig. I would suggest finding a complete 400 engine. Rebuild the bottom end with all the original parts as long as the rods and crank are machinable. Run a set of -21deg dished flat tops and top it off with a set of modified Vortec heads, a Lunati Voodoo cam, an Edelbrock RPM Air Gap, and a 750 Holley. You'll get 425 horsepower all day long and it'll be super reliable. You could make it a daily driver as long as you don't mind buying tires every few weeks from the killer burnouts that this torquey motor will produce. And best of all, it'll be easy on your budget. You could save money that could be used in other places on the car.

ok thanks for the info, i wasnt sure. i was planning on putting a performer rpm manifold, performer rpm cam, but i will look into the cam you said.

The 4-bolt blocks (part# 3951511) can safely hold up to around 400-425 horsepower with excellent reliability.

FYI:

I have a 2-bolt (part# 3951511) block. So you just can't go by the numbers. Best sure fire method is to pull the oil pan.

Look up info on Dirt Reynold's build. It's a great place to start for a budget 400 build. Try looking through the Vortec sticky also, since a lot of info has been posted on 400 combos.

Have you considered a crate engine? If you are not an experienced mechanic and plan to do all the work yourself, you might find this task quite an uphill struggle. To get the HP numbers you are looking for, you will need to be very accurate with tolerances, and this will require a number of precision tools to get things right. Building a daily driver motor is not that difficult to do, but the more power you expect, the more critical proper engine assembly is.

There are plenty of custom engine shops around that will build motors to your specs. I know that there are several board members here that are located in BC, and will probably speak up pretty soon. I understand the thrill of putting together a killer motor by yourself, but you really should have some experience before you drop a ton of $$$ into something that requires a good deal of time, effort and ability. Good luck.

Have you considered a crate engine? If you are not an experienced mechanic and plan to do all the work yourself, you might find this task quite an uphill struggle. To get the HP numbers you are looking for, you will need to be very accurate with tolerances, and this will require a number of precision tools to get things right. Building a daily driver motor is not that difficult to do, but the more power you expect, the more critical proper engine assembly is.

There are plenty of custom engine shops around that will build motors to your specs. I know that there are several board members here that are located in BC, and will probably speak up pretty soon. I understand the thrill of putting together a killer motor by yourself, but you really should have some experience before you drop a ton of $$$ into something that requires a good deal of time, effort and ability. Good luck.


sorry i forgot to say that my dad is a mechanic, he will be helping me out on the build. hes built alot of sbc...

Personally I would run a 2 bolt block and a stroker crank for around 420ish cubes if you are buying a new rotating assembly. 6" rods for internal balance and light light light pistons. Shoot for a compression ratio around 9.5-10.5:1.
Stud it, plug the deck, and run a decent hydralic flat tappet cam and a good set of heads. Keep the power peak below 6000rpm and make it a brutal torque motor. Makes it reliable and requires less gear and converter. Cam choice is critical.

I really like the Eddie victor jr's for bang for the buck. The Dart pro-1's (platinums) I hear are really nice also and inexpensive. Go for the 215cc or less intake ports. If you can swing the bucks I would run AFR 195's or 210's. I woudl run and Edelbrock Performer RPM Airgap and 750 holley.

You want your cranking pressure with the cam to be around 175psi for pump gas. You can get away with a little more in a light car with lots of gear and converter, but I find 175psi to be pretty trouble free in most situations on 93 octane.

You should make an easy 450hp, but 500+ft-lbs of torque withour trying too hard.

Dirt's 400 build with vortechs is hard to beat for bang for the buck however.

Andrew1977, what is the end use of this motor gonna be? Is it strictly track or is this intended to be a streetable combo? Also, RacerRick, what kind of side-effects would you get if you plugged the deck? My understanding is that with the siamesed bores you want the holes open to release trapped steam, especially with a street motor.

Rebuild the bottom end with all the original parts as long as the rods and crank are machinable.

With the guy wanting to spray it and hope for 600hp, I don't think I would want to use the stock bottom end.

If the budget allows, go forged.

Great advice from Alex71RS.

Only thing I might change is the carb to a Edelbrock Performer but I'd have to see the specs on the cam he recommenced to see if it has good vacuum at idle. I'm not a big fan of Holley carbs on the street. The Edecbrock Performer (a Carter AFB with a Eddy sticker on it) is a much more streetable carb and yet it will perform well too.

Do yourself a favor and do a search here on carburators. You'll see a lot of opinions on them but read the ones with common sense and experince. (Sorry, Alex71RS, if I sound like I'm dissing you, but I'm not a big fan of Holley carbs on the street from experinces with them). IMHO, they are a great carb on a high performance engine with intake vacuum issues at idle.

ok this summer im getting a bunch of jobs and i want to build a killer motor to put in next winter. i want around 500 naturally asperated hp. im not sure if i should build a 383 or a 400. i would put forged crank, forged rods, and flat top pistons. im definetly not an expert at this so im not sure how much hp this could hold. if i was to use billet main caps would this help with stength? my internal parts would probrably be: Eagle H-beam 4340 rods, Eagle 4340 crankshaft. i would probrably want to put nitrous system on. with nitrous id like to achive 600 hp at least. my question would be; will the block hold together with around 600hp? or should i get like a world block? BTW dont make fun of me.. im a newbie:crazy:

If you have the budget to even consider a World (or Dart) block, then that is certainly the way to go. They are infinitely tougher in all the right places and you don't have to sort through a bunch just to find one that isn't cracked or used up. They are also pre clearanced in all the right places whereas the GM blocks need some grinding at the bottoms of the cylinders to clear the rods.

My second choice would be to install the front 4 steel main caps, with the center 3 being splayed 4 bolt caps.

My third choice would be a factory 4 bolt, we haven't come across one of them that is cracked anywhere in the mainline, and the 3 center caps are nodular iron and considerably stronger than the grey iron caps of the 2 bolt.

I wouldn't even consider a 2 bolt if you're looking for 600 HP, you're throwing your money away at that point and will have mainline issues.

As far as cranks and rods I like the Scat products for the budget minded customer. I personally run one of their Superlight 4340 cranks and their 6" H beam rods and was very impressed at the fit, finish, and journal straightness. We've used lots of their Pro Comp and standard weight cranks, as well as countless rod sets. Nothing to complain about from where I'm concerned.

If you have the budget to even consider a World (or Dart) block, then that is certainly the way to go. They are infinitely tougher in all the right places and you don't have to sort through a bunch just to find one that isn't cracked or used up. They are also pre clearanced in all the right places whereas the GM blocks need some grinding at the bottoms of the cylinders to clear the rods.

My second choice would be to install the front 4 steel main caps, with the center 3 being splayed 4 bolt caps.

My third choice would be a factory 4 bolt, we haven't come across one of them that is cracked anywhere in the mainline, and the 3 center caps are nodular iron and considerably stronger than the grey iron caps of the 2 bolt.

I wouldn't even consider a 2 bolt if you're looking for 600 HP, you're throwing your money away at that point and will have mainline issues.

As far as cranks and rods I like the Scat products for the budget minded customer. I personally run one of their Superlight 4340 cranks and their 6" H beam rods and was very impressed at the fit, finish, and journal straightness. We've used lots of their Pro Comp and standard weight cranks, as well as countless rod sets. Nothing to complain about from where I'm concerned.

well i do have a budget, but if absolutly have to go with a world or dart block to run 600 hp then i will have to do that. if i can get away with 600 hp with a stock 4 bolt block without it grenading i would rather do that. the reason why 500 hp is too low is because my dad just got a vortec supercharger for is 2000 mustang GT and i want to beat his car at the drag races. i want the motor to be able to be drivable on the street.