A little more HP out of my 400

[YY1]

I had a 77 400 from a van in my 70 Super Bee for a while.

It actually ran real good and almost as much power/fun as the fresh 70 383 that replaced it.

I was surprised as there were a lot of people trash talking 400's even back then.
My expectations were low, but they were far exceeded.

I agree the axle gear certainly makes a difference- mine was a 3.55.

 

[Curiousyellow71]

This is Lengthy but will share my 400 story.
We have a 72 400 2 barrel that started out in a Fury II that my grandparents had. It had 78k miles when it was parked in the 80s(similiar to the op's) When I was in high school we spun a bearing in the 440 in our 69 charger and we pulled the engine out of the Fury and moved the headers and 4 barrel TQ over to the 400. Shift kit and 3.23 sure grip. We had fun with it and we drove it hard till the timing chain affected how it ran. It ran decent even with the 2 barrel cam.

We then pulled the 400 and it sat for a couple months. And this particular 400 story gets colorful..Dad had purchased a dozer that the engine was blown up and we needed to get it home. My brother and took the wrecker over pulled the diesel and in went the 400. The power steering pump powered the steering and the 727 was used for gear reduction. We drove it 9 miles home. The dozer originally ran 1400 rpm full throttle it was incredibly snappy with the 400 4 barrel. Track made quite the racket over 20mph! On the way home after the 3rd mile I had to make a left hand turn with the dozer...but I didn't make it, So I needed to backup. To operate the throttle we had a wire tied to the dash to the thermoquad. The dash flopped around as it only had a couple bolts in the lower part...so when we pulled on the dash the wire opened up the carb. But...to shift you had to get out of the seat, crawl under the dash into the belly and grab the shift lever on the 727. Well... when I went to crawl under to shift it in reverse. I supported myself by reaching up for the dash pulling on it..kicking in the secondaries of the thermoquad. It was now full throttle and It revved so quick in 5' it had already shifted from first to second..me riding the 727 like it was a saddle on a horse headed for a Power pole. Somehow I got stopped but it was a very exciting 10 seconds of my life. We had fun playing with it for a few years before we put the diesel back in and we pulled the 400.

The 400 then went in a Volare, got a new timing chain,440 six pack cam, headers, 3.55s w sure grip, It would leave Black marks all the way through first gear and likely was near 300hp.
Lots of fun till it spun a bearing after a year of burn outs...and we built another 400 with 346 heads cut .070 to 74cc and a 218/218@ .050 .455/.455 cam. Surprisingly we liked the six cam better. But it was a different short block likely in a lesser condition.

Final chapter for the 72 400. It was stroked and bored and is now a 542. It is going in our 72 Satellite sebring. We are nearly double the op's goal but externally it look stock.
400s are very underated with a taller decks then a chevy 454. Their is a reason they are loved for strokers.

 

[RJRENTON]

This is very,very Lengthy but will share my 400 story.
We have a 72 400 2 barrel that started out in a Plymouth Fury II that my grandparents had in the late 70s. It had 78k miles when it was parked in the 80s. When I was in high school we spun a bearing in the 440 in our 69 charger and my brother and I pulled the engine out of the Fury and moved the headers and 4 barrel TQ over to the 400. Shift kit and 3.23 sure grip. We had fun with it and we drove it hard till the timing chain affected how it ran. It ran good enough that at one point it broke the motor mount sucking the accelerator pedal to the floor and jammed the shifter into Low and kept revving till my brother got it into second and the gas pedal came back. Car still has a dent in the hood from that day.

We then pulled the 400 and it sat for a couple months. And the 400 story gets colorful..Dad had purchased a relatively big 55,000 lb dozer that the engine was blown up and we needed to get it home. My brother and took the wrecker over pulled the diesel and in went the 400. The power steering pump powered the dozers steering and the 727 was used for gear reduction. We drove it 9 miles home. The dozer originally ran 1400 rpm full throttle it was incredibly snappy with the 400 4 barrel @5000rpm. It went fast enough to scare the sh#t out of you. On the way home after the 3rd mile I had to make a left hand turn with the dozer...but I didn't get the left track to stop enough to steer and turn left. So I needed to backup... You could hardly see the engine sitting in the frame( original diesel was 1091 cu inches) and this was a quick get in running and moving deal. We had a wire tied to the dash face to the thermoquad The dash flopped around as it only had a couple bolts in the lower part...so when we pulled on the dash the wire opened up the carb. But...to shift it you had to get out of the seat crawl under the dash into the belly and grab the shift lever on the 727. Well... when I went to crawl under to shift it in R... I was directly on top of the 727 with the exhaust manifolds dumping right in my face. It was all well and good but as I reached for the transmission I supported myself by reaching up for the dash pulling on it..kicking in the howling secondaries of the thermoquad. It was now full throttle and It revved so quick in 5' it had already shifted from first to second..me riding the 727 like it was a saddle on a horse headed for a Power pole. Somehow I got stopped but it was a very exciting 10 seconds of my life. We had fun playing with it for a few years before we put the diesel back in and we pulled the 400. It got a new timing chain and oem cam out of our 440 six pack, headers, 3.55s w sure grip, and went in a volare for my youngest brother. It would leave Black marks all the way through first gear. Lots of fun till it spun a bearing and we built another 400 with 346 heads cut .070 to 74cc and a 218/218@ .050 .455/.455 cam. We were a bit disappointed the six pack cam seemed to run better.
Final chapter for the 72 400 is it was stroked and bored and is now a 542. It is going in our 72 Satellite sebring. It is in the spirit of F.A.S.T racing. Factory iron heads that flow 320cfm and tweeked everything. 400s are very underated. You can do lots and lots!

Your story about transplanting a 400 B block Mopar is interesting.....but....the OP was looking for more "a little more power" for his X-country journey in his car.....your tale about pulling a diesel engine and replacing it with a gas engine.....but it sounds like the "agony and ecstasy".....how were all the interface issues accomplished? Power train, cooling, fuel control, ignition system, etc. An ~1000 c.i.d. diesel capable running at 1400 RPM all day at full load with a carburetorated gas engine turning 5000 RPM peak load for a few minutes may be possible but not anything like the diesel's capabilities or longevity. Why not just fix/repair the origional diesel engine? The time and $$ expended would favor the diesel repairs vs the reliability of a gasoline engine of half the torque capabilities. BTW...who made the origional diesel? Cummins or Cat or GM/DDA/Allison....just curious.....in industry, having been involved with field overhauling all three brands, the Detroit (8V-92 Turbo) was the least expensive while Cat (3412 twin turbo) was the most expensive, and the Cummins 855-L about in between ......just my opinion of course......
BOB RENTON

 

[WileE]

Guys, guys, you are all VERY knowledgeable that posted here, I know that. Please read what the OP noted in post #1: "Want to boost the HP on my 400 to maybe 300 to 350 without going into the bottom end," ... someone please explain to me how he's getting there on a low-compression smog engine with just a cam.

 

[Curiousyellow71]

Your story about transplanting a 400 B block Mopar is interesting.....but....the OP was looking for more "a little more power" for his X-country journey in his car..... The time and $$ expended would favor the diesel repairs vs the reliability of a gasoline engine of half the torque capabilities. BTW...who made the origional diesel?
BOB RENTON

You must have missed the post where 3 cars ran a 400 with a stock short block (like the op) and added bolt ons. Headers were added, cams, heads, and gears were changed. All ran pretty good, nothing fancy. You could drive them anywhere. The op has not put forward any dollar targets so I am not going to go beyond such things. Heads make hp. Cam changes are compromises.
We had to pull the dozer engine either way. It started on gas then you switched it to diesel made by IH built in the 50s. We eventually found a replacement like the original. It was long before we owned a semi and a detachable lowboy to get it to the shop. It was cheap to throw in the mopar and only took a day and we had some fun with it. It would scoot and was a fun project for a couple teenagers. As it happens it was a similar engine to the op. Dozer project was meant to be a humorous tale from 30 years ago ....nothing more. Maybe you get that...maybe not...either way that is OK.

 

[Wietse]

Guys, guys, you are all VERY knowledgeable that posted here, I know that. Please read what the OP noted in post #1: "Want to boost the HP on my 400 to maybe 300 to 350 without going into the bottom end," ... someone please explain to me how he's getting there on a low-compression smog engine with just a cam.

Simply answered, he is not.
I remembered reading about those cams specifically made to give those smog engines a boost without the need to dig any deeper in the engine, which could be an option for the OP to consider.
I see on the Hughes website the 440 cam made 415hp, not sure about the other mods but going by the picture it went with headers, aftermarket intake and 4-barrel carb.

 

[Geoff 2]

Wietse,
What Hughes description of their cam shows how ignorant they are, not what they know. As I already said, they can make any claim they like...doesn't mean it is true. They are actually doing a great disservice.

Have a look at any of the descriptions of these cams with the silly names, Bootlegger, Mother Thumper. They all have a number of things in common: tight LSA & lots of exh duration. And the companies that are honest in their description say they need COMPRESSION. The large overlap these cams have produce a raspy exh note. Great for sound, not so good for performance.

Lunati Bootlegger. Almost identical specs to Hughes. 232/244 @ 050; 107 LSA. Description says choppy idle [ if you are lucky ] 3000 stall, 3.73 gears and 10+:1 CR.
These would be a tq killer in a low CR engine.

 

[Wietse]

Geoff, good to know these cam company's are wrong and you are right about this.

 

[Geoff 2]

Erson cams has this WARNING in their cam catolog. The warning about excessive duration is ONLY in the BB Chrys. No other brand has this warning.

 

[Geoff 2]

Sorry,
Wrong page.

 

[Geoff 2]

Wietse,
Get some glasses. I NEVER said the cam companies were wrong. I have given three examples Crane, Lunati & Erson of rough idle to support my statement.

I said Hughes were wrong & they are not a cam company. They sell cams they buy from other people.

 

[Wietse]

Geoff, you are the one needing glasses and actually read first before replying.
I highlighted several times already that that Whiplash cam has been specifically designed for stock Low compression engines, 8,5:1 CR.
You continue to refer to engines with 10.0:1 or higher ratio's which is a different story and this cam will be very hard to run with that, you need race fuel for a start and driveability is non existent as you will be smoking tires all day long.
If you were right, Hughes engines as a company would not have survived by selling bullshit....
And that warning you are referring to applies to ANY make/model camshaft, you can select any brand long duration camshaft and it will make lots of horse power on high rpm but is going to be a dog of the start as it is not producing any torque at low rpm.
I would say that is basic knowledge about camshafts......

I am not going to continue this needless discussion as this is not helping anyone, I only suggested an option and if OP is interested he can contact Hughes for more information and take it from there.
It is up to the OP to decide how to get there in regards to costs/labour/results.

 

[Geoff 2]

Wietse,
Once again you got it wrong. Get some glasses. There plenty of people running these type of cams with 10:1 or higher....& not using/needing race fuel. Maybe someone will chime in. My quotes about 10:1 CR etc came from the cam companies. I am quoting their info, but for sure, I agree with them.
You can put any cam in any engine; that does not mean it will give the desired performance. Low CR engines need more care in cam selection.

You keep on believing the BS. May be you believe the earth is flat because someone said it is...

 

[fratzog lover]

The slug 400 on the dyno.

Understand from the get-go, this isn't a high performance 400 B engine build. This is what the customer wanted for his '72 Dodge pickup. Lots of things could have been done differently. But with the instructions, "My employees will be driving this truck, I don't want anything wild," we settled...

www.forbbodiesonly.com

 

[fratzog lover]

And this is just cast stock type pistons and 7.5 compression. Use this as a baseline and tweak yours as you see fit. It can be done.