Can a 400BBM w/cheap aluminum heads compete/dominate against the street LS?

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greymouser7

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Planning BBM purpose/capability versus investment.

Competing against 6.2 & 408ci LS strokers, LS7’s

What would it take to/can a 400BBM Compete against other well-sorted LS street engines?

thanks for your consideration!/time!!
 
The biggest problem with a stock BBM 400 is Compression ratio.
If you are looking to rebuild a good set of pistons is the way to go.
That matched to the heads,matched to the cam,,etc.
I had a stroked 400 to 451 with Edelbrock heads that was a beast of a engine.One of the best engines I ever owned.
 
Step one, if i was trying that , would be getting the best heads you can afford. Step two would be stroking it to 470, or 512 inches. Step three would be a big nitrous setup.
I have a friend who has a stroked 408 LS with a single turbo, in a street driven 78 malibu. It makes 1200 at the crank. Pretty high bar to get over.
 
I don’t mind losing to more money, and most here (SATX) don’t sport so much effort; I am aiming for the LS swap guys or the occasional LS build. The 400 I have was $250, speedmaster heads were $500+ ...am not looking to fight Tyson for the championship, just whatever the average contender is that pulls up besides me.
Step one, if i was trying that , would be getting the best heads you can afford. Step two would be stroking it to 470, or 512 inches. Step three would be a big nitrous setup.
I have a friend who has a stroked 408 LS with a single turbo, in a street driven 78 malibu. It makes 1200 at the crank. Pretty high bar to get over.
Would adding a TURBO to an LS be that cheap or an expensive endeavor?
 
It is the ports that make the LS motors the beasts that they are. GM did a lot of R&D on ports and flow. I wish some one would do a total redesign on the mopar heads SB & BB.
 
Seems to me the best way to go about this is to put the engine in the lightest body that it will fit in.
 
It is the ports that make the LS motors the beasts that they are. GM did a lot of R&D on ports and flow. I wish some one would do a total redesign on the mopar heads SB & BB.

Wish in one hand and crap in the other and see which one fills up first. lol
 
Stroke it and do some good head work and you get what....maybe 600hp? Will that be competitive in the car you sre going to run it in?some yes and likely against any power adders no.
 
Part of the trouble is, as brian6pak said, the ports is what makes the power. Plus the possible stout roller cam with killer rocker ratio, and a six bolt bottom end. Means far better breathing and power per cube, and lots of rpm. An ordinary truck 5.3 has way more power, and potential than a stock 400.
And, turbo kits for 400/440 are almost non existent, there are chinese turbo kits for a 5.3 ls than can almost triple stock output, for reasonable money. (Why i suggested a nitrous kit, they fit everything).
Dont get me wrong, i LOVE my big block mopars, and since i know nothing about the ls fuel injection, i will never do an ls. But i understand why they are the most popular swap around.
 
I don’t mind losing to more money, and most here (SATX) don’t sport so much effort; I am aiming for the LS swap guys or the occasional LS build. The 400 I have was $250, speedmaster heads were $500+ ...am not looking to fight Tyson for the championship, just whatever the average contender is that pulls up besides me.

Would adding a TURBO to an LS be that cheap or an expensive endeavor?
There is undeniably serious money in my friends car, and way more in his next ( KB solid block hemi with a procharger, in a promod avenger), and his malibu is not your average street car.
Yes, i think your 400 can be competitive with the average street-rat ls, and without spending huge money. I gave you my recipe.
 
Part of the trouble is, as brian6pak said, the ports is what makes the power. Plus the possible stout roller cam with killer rocker ratio, and a six bolt bottom end. Means far better breathing and power per cube, and lots of rpm. An ordinary truck 5.3 has way more power, and potential than a stock 400.
And, turbo kits for 400/440 are almost non existent, there are chinese turbo kits for a 5.3 ls than can almost triple stock output, for reasonable money. (Why i suggested a nitrous kit, they fit everything).
Dont get me wrong, i LOVE my big block mopars, and since i know nothing about the ls fuel injection, i will never do an ls. But i understand why they are the most popular swap around.
It sounds like you’re saying Big blocks are irrelevant on the street.

I am under the belief that most car people (HERE) don’t have that kind of money, but they do soup up cars, and additionally LS swaps ARE cheap.

I realize that out in California, & in the NorthEast/big cities that there are plenty of people that can reach above 800-2000 horsepower, I am not concerned with big money cars.
 
There is undeniably serious money in my friends car, and way more in his next ( KB solid block hemi with a procharger, in a promod avenger), and his malibu is not your average street car.
Yes, i think your 400 can be competitive with the average street-rat ls, and without spending huge money. I gave you my recipe.
Yeah 500ci’s is an answer, but for the track. It would be hard to pass 8 gas stations with 500ci’s and a 3 speed auto
 
stroke to 451 or 470 with Trick flow 270 head to start your budget to even be competitive.
 
Do you have any limitations on axle ratio and convertor stall.
I could build a 400, but I would use a j convertor and a 4.56 or 4.88 gear, maybe 5.13.
 
Follow 4 out of 7, 7 C rules and you can get it done pretty OK.

Carb
Cam
Converter
Cog’s (gear ratio)
Cubic inches
Compression
Cylinder head

I’m not sure where you stand with the cylinder heads.
A Torque Storm super charger is not to expensive. But the upgraded fuel and ignition costs can be difficult to add on top when the bottom line is a concern. Gap your rings to suite and keep it under 10lbs. Oh! You’ll make power! And then what RRR said, a light car.
 
When comparing the LS stuff the BBM, you are comparing apples to oranges. The differences are great, 50+ year old Mopar stuff the to late model LS stuff. Besides, with all of the aftermarket stuff that's out there for the LS, anyone can build a cheap 400-500 HP LS. Be a real man a build a NA killer stroked 400 & show the LS boys how it's done.
 
Planning BBM purpose/capability versus investment.

Competing against 6.2 & 408ci LS strokers, LS7’s

What would it take to/can a 400BBM Compete against other well-sorted LS street engines?

thanks for your consideration!/time!!
If it's built for a purpose and if you don't mind spending the $ on good fuel you can do it rather cheap. You really are not going to drive it much so the fuel will not kill ya. I'll be right back.
 
The 6.2 LS in Matt's truck is 638HP to the rear wheels. Naturally aspirated with "some kinda" high fallootin EFI setup on it. NO power adders. I've ridden in it several times. I believe the numbers are accurate. So, I'd "be careful" goin after LS motors.
 
Forced induction is the way to go. The engine itself is stout enough, put a huffer on it.



I have a running '73 motorhome 440 and a 440 6-71 setup that I'm gonna screw together one day into a time bomb...
 
LS motors are efficient and the blocks are strong, but they're not huge power makers without a lot of work. The heads seem to flow ~240cfm, TF270 heads flow 340 (600+ HP LS motors are using 350+ cfm aftermarket heads). The bore of the BBM is larger, so more torque right off the bat. The big advantage with LS motors is that there's millions of them, and parts are cheap, proven combos are well known, and the blocks are capable of dealing with immense power/stress.

I can't imagine a 400 with TF270's not having an advantage over an NA LS motor - the BBM wouldn't even need a stupidly huge cam to overpower most NA LS motors. Get a set of 1.7 rocker arms, and the number of advantages of the LS motor shrink further. The BBM likely won't get the MPGs an NA LS motor does, but it should be decent if the cam isn't too huge. With a solid cam, I can't see why you can't spin the 400 to 7-7500 rpm either (with appropriate prep and combination, obviously). With decent compression, 5-600 streetable HP should be attainable with a stock stroke I would imagine (many 451+ CI motors are well over 700 horse).

Whether more stroke or other tricks would be needed would depend on your quarry. If you're just looking to 'keep up' on the freeway and stoplight to stoplight, I think a 400 can be put together for a reasonable amount that can do just that. Being competitive with strip-built LS powered cars is something entirely different (since they're going to have aftermarket heads and cams more often than "LS swapped" junkers). Power-added LS motors are a different beast entirely because the blocks have such immense strength that huge NOS systems and big turbos are not uncommon.
 
Planning BBM purpose/capability versus investment.

Competing against 6.2 & 408ci LS strokers, LS7’s

What would it take to/can a 400BBM Compete against other well-sorted LS street engines?

thanks for your consideration!/time!!
Just what are "well-sorted LS street engines" anyway? The whole question is to damn vague for me.
 
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