randy400
New Member
Can anyone tell me if I can swap 383 or 440 heads/intake manifold on a 400 and if that would help the performance
More power out of my 400 charger
- Thread starter randy400
- Start date
the heads for for the B/RB engines will interchange. intake manifolds for 383/400 will not fit 440 and vice versa. as for performance gains improved heads flow and valve size and correctly match cam and intake
will for sure wake the 400 up.
will for sure wake the 400 up.
randy400
New Member
Thanks beekeeper, I have a extreme energy cam that's rated 1800 to 6000 rpm but a weiand high rise intake that's 2700 to 7700 rpm . Just a street performance is all I'm after. Planning on an edelbrock performer and started thinking maybe change heads at the same time. Or just get mine ported and polished. How do I get a pic on my profile. My 72 looks close to yours
I did a slouchy 400 in a 73 charger, we changed out the intake, carb, cam, and ignition system, woke that guy up a good bit, and actually helped with fuel economy, lol, not sure how that worked but mpg went up...
The cam was a 252H if I remember correctly, carb was one of the barry grant street models, intake was a holley street dom with a 1" tall adapter plate, ignition was a mallory uni with their box and coil, all used stuff we had laying around except for the cam/lifter kit and carb we bought new... We gasket matched the intake and we installed headers and 2.5" exhaust on that car, with a big round intake and kn filter, we also did the b&m improver kit in the tranny while we had the car on the lift and the pan was rough enough to warrant changing, last thing we did was swap in a new ring and pinion with a posi center, car had an 8 3/4 with 2.76 gears, I think we ended up installing 3.91s...
That car was like night and day after we were done, when I drove it to the garage the tires would NOT spin, if would fall on its face and bogg down, opening the 4bbl had to be done with care not to stall, it had low miles and my cousin bought it to play with and thought it was a pig because of old gas, lol... Anyway, we did the above work in a weekend, and I was the first to drive it, I pulled out of my driveway nice and easy went up a couple blocks after it was cleared out a bit, I hammered her and it was DIFFERENT, after a couple ignition adjustments, that car would BLOW sideways and catch second good gear on flat ground if you stayed in it while it shifted. My cousin couldn't believe the difference and to be honest neither could I...
The cam was a 252H if I remember correctly, carb was one of the barry grant street models, intake was a holley street dom with a 1" tall adapter plate, ignition was a mallory uni with their box and coil, all used stuff we had laying around except for the cam/lifter kit and carb we bought new... We gasket matched the intake and we installed headers and 2.5" exhaust on that car, with a big round intake and kn filter, we also did the b&m improver kit in the tranny while we had the car on the lift and the pan was rough enough to warrant changing, last thing we did was swap in a new ring and pinion with a posi center, car had an 8 3/4 with 2.76 gears, I think we ended up installing 3.91s...
That car was like night and day after we were done, when I drove it to the garage the tires would NOT spin, if would fall on its face and bogg down, opening the 4bbl had to be done with care not to stall, it had low miles and my cousin bought it to play with and thought it was a pig because of old gas, lol... Anyway, we did the above work in a weekend, and I was the first to drive it, I pulled out of my driveway nice and easy went up a couple blocks after it was cleared out a bit, I hammered her and it was DIFFERENT, after a couple ignition adjustments, that car would BLOW sideways and catch second good gear on flat ground if you stayed in it while it shifted. My cousin couldn't believe the difference and to be honest neither could I...
randy400
New Member
That's awsom! This started because I don't think my secondaries are opening, I don't hear it and feels like a straight slow pull. I was told that intake is mentioned for drag at high rpm. It's not creating vacuumed at lower rpm. Does that sound right to you
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Car Nut
Well-Known Member
aboard!
PurpleBeeper
Well-Known Member
Here's my 2-cents.
1. There will be little/no difference in 400 vs. 383/440 heads' performance. I believe that all of the big block heads made since 1968 are the same as far as performance goes. The '67 440 heads or other pre-'68 heads with larger '68+ exhaust valves might be a good swap for you since they're closed chamber and will raise your compression.
2. If you don't think your secondaries are opening, try putting in a different spring and/or check to make sure the diaphragm isn't leaking.
3. Short answer: nitrous
1. There will be little/no difference in 400 vs. 383/440 heads' performance. I believe that all of the big block heads made since 1968 are the same as far as performance goes. The '67 440 heads or other pre-'68 heads with larger '68+ exhaust valves might be a good swap for you since they're closed chamber and will raise your compression.
2. If you don't think your secondaries are opening, try putting in a different spring and/or check to make sure the diaphragm isn't leaking.
3. Short answer: nitrous
Bb70charger500
Well-Known Member
Just snatch out the 400 and find a nice 440 by the time you get done dumping money into the 400 you could probably get a decent 440 for the same money. I'm not a fan of 400's they can be bad *** race motors but will cost a lot to do so . 440 is easy cheap power . I'd deff play with your carb before you go switching heads . I had a car the secondary s wouldn't open it was a slug the guy didn't know what to do so he sold it saying it was to slow.I tossed the carb went withan eld and holy crap what a difference. Good luck
It looks like you have a real nice car, I am not a fan of the thermo bogs, I will tell you this, if you do not hear or feel them spread bore secondaries then they are not working because that is on thing about them, you hear them open, lol I had one that sounded like loud exhaust when it opened...
Route a vacuum gauge in the car (I have a 15 footer just for this, lol) you can also try to open them with a mity vac if you have access to one...
But honestly if you have the funds and want performance, change the cam, intake, carb, may as well change the timing set, and the ignition to something that can light the fuel, and you will never look back, the car will run better, be more reliable, and have a lot more power...
You can get msd or mallory rb ignition systems cheap on ebay, pertronics, and a few others work well also, I like something with a rev limiter and multi spark is nice. I would call Promax and see what he has and have him build you a carb, he will build you a holley for that car for $300ish that will be better than anything you can buy off the shelf, and he will set it up where you can pretty much bolt it on, he will also have good input on a cam.
Figure a cam set, timing cover gasket, intake gaskets, and carb gasket, timing set, used ignition, promax carb, and used aluminum intake will set you back about $900 and make a bigger difference then any set of heads you bolt on.
BTW, if you are looking to get different heads, I was always partial to the 906's, every fast cast head 440 I have been in had 906's, its my favorite head, I have a few sets sitting in the shed, 1 set all built, 1 all machined just not assembled, and 1 untouched take off. You can buy them super cheap unrestored, pay $200ish for them to be magged, cleaned, matched, and comp valve jobbed, $100 for valves and locks, $100 for springs and retainers, and you have a nice set of heads, BUT if you were to unbolt yours and bolt the set I have on you probably wouldn't notice a difference in your seat. With what I outlined above, you will notice a difference...
Route a vacuum gauge in the car (I have a 15 footer just for this, lol) you can also try to open them with a mity vac if you have access to one...
But honestly if you have the funds and want performance, change the cam, intake, carb, may as well change the timing set, and the ignition to something that can light the fuel, and you will never look back, the car will run better, be more reliable, and have a lot more power...
You can get msd or mallory rb ignition systems cheap on ebay, pertronics, and a few others work well also, I like something with a rev limiter and multi spark is nice. I would call Promax and see what he has and have him build you a carb, he will build you a holley for that car for $300ish that will be better than anything you can buy off the shelf, and he will set it up where you can pretty much bolt it on, he will also have good input on a cam.
Figure a cam set, timing cover gasket, intake gaskets, and carb gasket, timing set, used ignition, promax carb, and used aluminum intake will set you back about $900 and make a bigger difference then any set of heads you bolt on.
BTW, if you are looking to get different heads, I was always partial to the 906's, every fast cast head 440 I have been in had 906's, its my favorite head, I have a few sets sitting in the shed, 1 set all built, 1 all machined just not assembled, and 1 untouched take off. You can buy them super cheap unrestored, pay $200ish for them to be magged, cleaned, matched, and comp valve jobbed, $100 for valves and locks, $100 for springs and retainers, and you have a nice set of heads, BUT if you were to unbolt yours and bolt the set I have on you probably wouldn't notice a difference in your seat. With what I outlined above, you will notice a difference...
Bb70charger500
Well-Known Member
I do have a set of 906 heads I'd be willing to sell if you can't get any came off of a 69 383 hp motor. (I have the whole thing actually) also a torquer intake too if interested p.m. me
Phil McGrath
Well-Known Member
Minus the pistons anything that works on a 383 will work on a 400. All you really need is a good set of pistons too get the compression up. The 400 actually has a larger bore than the 440RB does. A good running 400 built the same as a 383 can make a honest 400hp without breaking much sweet or working real hard.
451Mopar
Well-Known Member
The biggest issue with a stock 400 is they had really low compression ratios. The 400 has the largest stock bore size of any of the Chrysler engines. It is basically a large bore, low compression 383 engine.
You can build a performance engine with the stock low compression short block, but low end torque will suffer, but with a high stall converter and plenty of gear I have seen them perform pretty good.
Put a machined down 440 crank in and you get about 451 CID (with new pistons.) 440 source has several stroker kits that will make the engine a beast, but cost some $$$$.
If you just want to do a head swap, the Brodix B-1 B/S heads have small 65cc chambers that will help bump up the compression ratio.
You can build a performance engine with the stock low compression short block, but low end torque will suffer, but with a high stall converter and plenty of gear I have seen them perform pretty good.
Put a machined down 440 crank in and you get about 451 CID (with new pistons.) 440 source has several stroker kits that will make the engine a beast, but cost some $$$$.
If you just want to do a head swap, the Brodix B-1 B/S heads have small 65cc chambers that will help bump up the compression ratio.
I saw where you were thinking of adding the Edelbrock performer intake. The performer is a slight upgrade from the stock iron intake, according to Edelbrock sight. I took mine off and added a torker single plane and made a huge difference. The torker was free! So I used it. If not, I would have bought the performer rpm.
i would take a look at the Edelbrock performer rpm intake instead of the regular performer. It's the best of dual and single plane world combined.
Good luck..
i would take a look at the Edelbrock performer rpm intake instead of the regular performer. It's the best of dual and single plane world combined.
Good luck..
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seems like some good advise here
seems like some good advise here
KarNut46
Well-Known Member
You didn't say if you have a thermo-quad. If you do you need some fairly accurate info to make it work properly. I work on a lot of Q-jets and the t-quad is real similar. There are a lot of misconceptions about the carb floating around. 1) secondary air valves (the valves you can see in secondaries w/ air cleaner off) are held shut by the vacuum pot that is located on pass. side rear of carb. It doesn't open the air valve it allows the valve to open at a prescribed rate by way of a restriction in the vacuum passage leading to the pot. If the vacuum pot ruptures the secondary air valves will open way, way to fast resulting in the famous bog that gave the carb the nickname "thermobog". With engine at idle check to see if the vacuum pot holds the air valve shut. Should take some pressure to force the air valve open if pot is working properly. 2) Secondary throttle valves (in base of carb) can get corroded and stick to the throttle bores. Secondary valves are opened mechanically. Try to open them manually by opening throttle wide open and looking thru top of carb (air valves open) to see if they actually open. If they fail to open try tapping on them w/ a short piece of dowell rod or something softer than alum. Be gentle, if you twist or bend the throttle shaft you'll have a more serious problem. Good luck on your project.
niteshift70
Well-Known Member
If money is tight, you can go to thinner head gaskets and/or have the heads shaved to bump up the compression to match a somewhat larger cam (basically reducing the combustion chamber volume.) Keep in mind that once the head is milled so far, the intake side of the head needs to be shaved as well to keep both surfaces in the proper relation for th intake manifold to fit properly. A quick call to any good mopar shop that does machine work on the OEM cast iron heads and they'll give you recommendations on how much you can or need to shave to get the results you want (some shops that don't do their own head machining will just tell you you just gotta have those expensive aluminum jobs.) The thermoquad (if rebuilt properly) will perform as well as any carb out there AND get much better mpg than any holley and as good or better than any avs clone (i.e. edelbrock.) Summit Racing actually has its own line of remanufactured thermoquad out now.
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