First Dyno Tests On New 421sbc Dyno Mule: Big Headers Big Power

Better tighten that valve cover back up lol

Bigger stick will be interesting.... another 50hp my guess...7500rpm.. Thanks for sharing the results..

Nice work Eric.
Certainly a nice combo.
Have a great week. 👍

Eric
What is the port volume and cross section on that 421 head?
The larger tube diameter slowed running airspeed down away from choke
FPS

Is that the one you had at Bob's?

I'm curious to see a video on the wing, there is some hemi guys doing one that looks about the same claiming big power from it. Does it help flow more or is it about getting the fuel in the right place?

I have a 489 that has a small cam, 218/226 at .050, and Brodix Race Rite 270s’, in hindsight I wish I had just bought them ported from you but that is another topic for another day. Anyway, the builders standard big block dyno headers were monster 2 7/8” primaries but as my truck was originally a peanut port 91 OBS the headers that were on it were 1 3/4” primaries and for giggles we swapped those on after a few pulls and actually picked up 10-17 lbs of torque in the 3200-4000 range which for this motor is the useful range. Eventually I think 2” will be on it when it finds a home but I mention this as I think the right header depends on what you are using the motor for.

Large cubes, small cam, awesome cylinder heads, and serious power.
The only downside. I bet mpg is horrible! 😂😂🤣🤣
I’m joking that’s why the smileys. Nothing like this gets good mpg. It’s about power not economy, I get it.
Long ago, My small block got 9.8 mpg with an 830 Holley on a cross ram. Yeah I really get it. But it sure was fun to drive!!

That looks like a tight lash cam with it only wanting. .014" of lash. Do you open up the lash some when going to 1.7 ratio? @WeingartnerRacing

I'd love to see you test different cam timing (106/108/110) with this engine, with a piece this efficient I'd hope the results would be very cut and dry.

That thing is stout! Very nice build and power. Eric, I assume the block and heads have steam holes?

Very nice motor barely seemed to even get near red line by just listening to it over the computer. I found it interesting that it gained and lost both power and torque, all depending on the rpm you're looking at. I was just glancing over the dyno from 6000 to 6500 ant its very interesting to me how the engine performs. Please keep in mind I am not a motor head, don't get me wrong I love em, just don't know enough about them. Still from a newbie/novice it's pretty interesting where engines breathe best. I only have an old Skip White Performance motor from 11-12 years ago that was dynod but never installed., has the pro comp style 210cc heads and the small 7cc dome forged 2618 pistons 4340 forged crank and forged h beam rods and a Howards Hydraulic Camshaft. Hey Mister Weingartner, do you have any tips or tricks for me on this engine before I install it in a street strip 65 Chevy 2 Nova, 350 turbo w 3.73 gears and a sometimes used 300Hp Zex perimeter plate?

I definitely want to see more camshaft in this engine

Question do you think a set of dart pro 1 345 are to big for a 496 bbc?

11.3 close to the LS test going to get interesting

I know you say it at the end of every video, but why dont you port cast iron heads? Just too dirty? Too hard on the tooling? Why?

Very nice engine!!!!!!

What block are you using an old 400chev or a newer dart block....i have a 1976 400+040 that i ran on the street with vortecs and a 750 it was around 400hp with a stock bottom end and compression.
My engine guy said dont waste your time on them old 400s there junk.
I was looking at a new rotating assembly and brodix heads

Great power! Cam worked just like you said! I think your channel is going to take off! Great content!

Summers Bros sales that front drive distributor. Alkydigger has a few front drivers of that style alsi for Sbc. Old school conventional style sbc is the best out there for power and reliability.

Automatic thumbs up.
Good stuff!

That's a great set up. I'd put it in a Fiberglass Vega street car. It would have some passing power.

Eric, I assume that the 1 3/4” vs 2” headers also had different collector sizes (3” vs 3.5”)?

Awesome job on the ported intake.

That is one nice SBC! Wow! Super cool thanks Eric!

May want to keep an eye on coolant pressure...the front expansion plug is protruding a little

Lots power

Monster mouse!

This is a test the appeals to me. Waiting for more. Thanks Eric.

Wow those headers made big difference. I seen similar results on a cammed LS3 with 2" primaries.

Put. Some. Good. Fuel. In. And. Nitro ous. Yeah. Buddy

The cylinder heads are good, the camshaft is not small for 11.3:1 compression. A better camshaft which will out accelerate this one on the drag strip, will have similar specifications with a hair more overlap, and a 106-107 lobe separation. BTW that's a 1 7/8" primary tube you're calling a 2". I'm not convinced it'll out accelerate the 1 3/4" primary tube on the drag strip. The first thing to look at when choosing primary tube sizing, is the exhaust port size. 427 sbc with Brodix Track One exhaust ports, the fastest header on a factory condition small tire n/a car around 3200 lbs is gonna be a 1 3/4" to 1 7/8" step, to a 2 5/8" choke, to a 3" collector. The first 60 feet is where you make your bones n/a 23 degree sbc.

lol the valvecover T nuts unscrewing themselves

Really nice combination! Will we see the other variants of your Dragon Slayers on this dyno mule?

1.44 ft/lbs per CI. Them’s big boy numbers

Eric as big as that motor is, I’d go bigger on the cam just to see what it does. My favorite Injected cam is an old Herbert and it’s 30 degrees longer

Hi Eric ,why do you take the extra time to flow test your heads on both of your flow benches when you could spend your valuable time generating income ?

Heck yeah man, very very informative video. Exactly what we need to know.

What size were the collectors? I’m curious as to when a 4” collector is needed.

I chose 1 7/8 adapter plate but the reason is 2 new sets of 1 3/4 both covered port opening. very unsatisfactory . My engine 400sbc with quality but lesser flowing cam /heads . A bump in tq /hp is great with better rpm hang time is a great result . Many thanks