Mark IV 454 Engine Build

[DSnyde34]

Hey everyone, I am about to buy a 74 K20 that has a Mark IV 454 Big Block in it. The truck currently needs a cam. I am fairly new to this so I was wondering if you guys had some advice on what cam to get and what other changes I should make. It currently has an Edelbrock carb on it. I was thinking it would be a good idea to put a new intake manifold on it as it still has the original cast intake. Should I just get an Edelbrock intake(Performer 2-O Intake Manifold #2161) since it already as an edelbrock carb? If I go with the edelbrock intake they recommend a camshaft(Performer-Plus Camshaft #2162) to go with it should I just go this route? I guess just what are your guys recommendations on a cam and what changes should I make to the motor to get more out of it without completely rebuilding it? Would new headers and exhaust be worth it? The truck is an old feed truck so I want it to have good low end torque because it will still be used to pull a trailer from time to time but I also want to be able to take it down the road and have some fun
Thanks!

 

[CalSgt]

The reality is any change you make will be a trade between reliability, efficiency and performance that old clapped out big block might not have much life left in it. If you want low end torque just put a stockish cam back in it & leave the manifolds alone.

An "RPM" intake is baby high rise geared toward higher HP while "maintaining drivability" (Edelbrock's words), most large tube headers are for high RPM performance some long tube headers with smaller primary tubes can be good for torque. Same for lumpy cams that sound good... they sound great at idle and perform better at higher RPM's, but produce less vacuum at idle.

What transmission is in it, what rear end gear ratio, and how tall are the tires? Dependent on this info maybe some high RPM performance will really wake the thing up.

If it has an SM465, granny low 4 speed, 4.10:1 gears and stock tires it might really like some added HP at high RPM's.

 

[squaredeal91]

I would put headers on it and get a quad back on there with aluminum intake. build it for torque. Advance cam timing a little too. Don't forget high volume oil pump. (Not high pressure) good quality roller timing chain. Do all the right stuff and you'll get decent fuel mileage and towing capabilities.

 

[idahovette]

Better look at the oil in it really close. If it wiped a lobe on the cam the metal had to go somewhere. There may not be much life left in that engine?/...just sayin' ..YMMV....Good Luck

 

[Catbox]

I can tell you first hand that you will love your engine after some simple upgrades.

My 454 was completely stock when it came to us.

You must be registered for see images attach

It had been rebuilt back in the April of 1990...

You must be registered for see images attach

You must be registered for see images attach

For the first upgrade we installed a set of headers from a 1968-72 Nova onto the truck as they fit like champs on the 2wd chassis. This made quite the difference in how it ran and drove already.
From the headers we installed a temporary 2-1/2" exhaust that dumps in front of the rear axle.
Quick and easy.

You must be registered for see images attach

They were a rusty set a buddy had that he wasn't going to use on his Nova again, so he gave them to me to test fit.
The headers went right on like they were made to be there, even went around the manual transmission linkage just fine.

You must be registered for see images attach

We drove it like this for a while before the next bunch of stuff was done to it....

 

[QBuff02]

I would go with the performer 2.0 intake as it has proven to be a good all around intake on a big block chevy, and I will also tell you that I had a Comp Cams XE262 in my 454 that I removed and went quite a bit bigger in the last rebuild and it was a great all around cam and had gobs of torque down low and through the midrange for what it was. However, that engine is now .060 over, domed pistons, 10.5:1 compression with a much larger/wilder cam in it, but it was a solid runner with a "small" cam in it. If you're using stock pistons you don't want to go too big on a cam or you'll just make the engine lazy/doggy. Just by looking at the advertised numbers on that cam and comparing to the comp grind i'd recommend the comp grind. And more air in= more air out. An engine is just an air pump so if you're going to put more in you want to get more out so i'd put headers on it if it was me and better exhaust. Did the current cam go flat? If so depending on how much debris went through it you might be money ahead to roll bearings into it as well at a minimum.

 

[Catbox]

For the next set of upgrades I took some time to find the deals that I wanted on the parts that work like a champ together.
I sourced a Edlebrock Performer 2.0 like you had mentioned for this version of the engine.
I have no plan on changing the cam out just yet, so it should work great for now.
It was found at a swap meet a few years ago for $125.

You must be registered for see images attach

At another swap meet last September I picked up the Holley 750CFM carb for the tiny sum of $40.
It was tinkered with on an engine that the PO could never get to run right.

You must be registered for see images attach

I gave Max my son the go ahead to buy the parts that he wanted / needed to rebuild it up to what we needed for the truck and he found all the things.
He went through all the steps to rebuild and clean the carb while installing the new gizmos too.

You must be registered for see images attach

The carb total came in around $200 for the purchase of the carb and all the bits you see above.

I have to say, the intake and carb changed the entire mannerism of the engine.
It is WAAAAAAYYYYY more fun to drive even with the stupid SM465 transmission in there.
Plus it looks much better to boot.

Here we are mid transition...

You must be registered for see images attach

Here it is all completed and running.

You must be registered for see images attach

 

[Catbox]

Here is a sample clip of it starting up now after all the fun has been added to it....

xc_hide_links_from_guests_guests_error_hide_media

We have since changed the mini starter out for a different one and the starter takes off like a rocket now.
The starter is off of a GMT-400 truck that had a small block in it.
They bolt right in and take off like a rocket compared to the old heavy stock starters.

 

[Catbox]

Another simple thing you can do to the engine that is fairly inexpensive is to swap the heads to a set of the GEN 6 heads.
These are the L-29 heads with a smaller chamber (100cc) than the peanut port heads (119cc) that may be on your engine. This has been said to raise the compression ratio to right around 9:1 compression.
Pretty much a full point of compression by bolting these on.

They have larger intake ports (235cc) than the peanuts (200cc-ish) as well.
I am only an enthusiast and have done research on the internets, so some may have more information than I do.
You just have to start looking around for them.

Here is one of the casting numbers....

You must be registered for see images attach

Down the intake port to the valves...

You must be registered for see images attach

These are the gaskets I have found will be the ones to work between the Gen4 and Gen6 engine parts...

You must be registered for see images attach

Here is the fast burn 100cc chamber of the L-29 head...

You must be registered for see images attach

I have found these in the junkyard for as little as $80 for the pair of them complete.
I also have a full L-29 engine that I intend to rebuild and put into the truck in place of the Gen 4 big block.
We found that one on half price day at the junkyard and it was less than $200 out the door.

 

[RanchWelder]

Catbox I'm about to dig into a Mark VI 454.
The injectors probably need to be swapped out.

How much max lift, did you find the L-29 heads will allow?

Are you going to stick with the rollers or go flat tappet with the "new to you Mark VI"?

Got cam numbers, I can check out?

I figure, if I have to pull the plenum apart to change the injectors, I might as well swap the cam and lifters, while I'm there.

Like the roller engine, however I'm not certain I can afford to rebuild the roller parts and it might have to go to a flat tappet with solid lifters and adjustable rockers... if you have a set of adjustable rockers, I'm interested in a set... or finding out what worked for your build...

 

[DSnyde34]

Thanks for all the replies! Catbox that truck sounds pretty sweet thanks for all the info.

The reality is any change you make will be a trade between reliability, efficiency and performance that old clapped out big block might not have much life left in it. If you want low end torque just put a stockish cam back in it & leave the manifolds alone.

An "RPM" intake is baby high rise geared toward higher HP while "maintaining drivability" (Edelbrock's words), most large tube headers are for high RPM performance some long tube headers with smaller primary tubes can be good for torque. Same for lumpy cams that sound good... they sound great at idle and perform better at higher RPM's, but produce less vacuum at idle.

What transmission is in it, what rear end gear ratio, and how tall are the tires? Dependent on this info maybe some high RPM performance will really wake the thing up.

If it has an SM465, granny low 4 speed, 4.10:1 gears and stock tires it might really like some added HP at high RPM's.

It does have the SM465 transmission, 4.10:1 gears, and stock tires. It also has the 205 transfer case which I believe is the good one.

Also, the truck is my uncle's so I know the history of the motor pretty well. The motor came out of one of my dad's old feed trucks that had an electrical fire under the dash. The motor always ran really well in that truck it was my favorite truck to ride in as a kid haha. My dad traded a guy some body & paint work for the motor. So I know the motor has been taken care of and hasn't had a really hard life. The motor doesn't have a ton of miles on it, my uncle only drives it a couple times a year and never more than 20 miles or so I'd say. That being said I am fairly confident the motor still has some life in it. I haven't got the cam out of it yet but when I do I'll be sure to look it over real close to see what all is wrong with it and I will check the oil really closely as well I appreciate the advice from everyone.

 

[Catbox]

Catbox I'm about to dig into a Mark VI 454.
The injectors probably need to be swapped out.

How much max lift, did you find the L-29 heads will allow?

Are you going to stick with the rollers or go flat tappet with the "new to you Mark VI"?

Got cam numbers, I can check out?

I figure, if I have to pull the plenum apart to change the injectors, I might as well swap the cam and lifters, while I'm there.

Like the roller engine, however I'm not certain I can afford to rebuild the roller parts and it might have to go to a flat tappet with solid lifters and adjustable rockers... if you have a set of adjustable rockers, I'm interested in a set... or finding out what worked for your build...

I am a super slow project completer.
Thanks Mom!

Due to that, I have not completed any work on the roller big block.
I will be using the roller cam for sure with the stock lifters.

For my use, I have been looking for the stock cam out of a ZZ502 engine:
The duration at .050" tappet lift (intake/exhaust) is 224/234
Lift with 1.7:1 rocker ratio (intake/exhaust) is 527/544.
Valve lash is zero/zero
Lobe centerline is 110 degrees.
This cam is intended to be used in Gen VI factory roller blocks.

Intended for factory roller blocks - 96' and up. Use with thrust plate and Gen VI timing chain set.
Single valvespring part # 12462970
Technical Notes: Distributor P/N 88961867 or melonized distributor gear P/N 10456413 must be used

This should make for a rowdy 454 with an internet guestimated 450hp and 500 ft/lbs or so.
The youtube clips of this combination sound good and seem to be plenty for our application.

A fine gentlemen on this board has rebuilt the later model 454 with the stock style injection for his truck.
That would be Eric or @Bextreme04 and he should be able to answer more of your questions than I can at this time.

 

[RanchWelder]

OK. I'll check Bextreme04 for max valve lift with stock Vortec Heads.
The ZZ502 you posted: Lift with 1.7:1 rocker ratio (intake/exhaust) is 527/544.

...sounds good. The ZZ502 is carbureted, and uses Chevrolet Performance Aluminum Bowtie heads. It's not rated for a computer controller though.

I'm not certain you could run it on Cast Iron heads... or if I want to ditch the computer at over a mile high elevation.

Good info...

 

[Bextreme04]

OK. I'll check Bextreme04 for max valve lift with stock Vortec Heads.
The ZZ502 you posted: Lift with 1.7:1 rocker ratio (intake/exhaust) is 527/544.

...sounds good. The ZZ502 is carbureted, and uses Chevrolet Performance Aluminum Bowtie heads. It's not rated for a computer controller though.

I'm not certain you could run it on Cast Iron heads... or if I want to ditch the computer at over a mile high elevation.

Good info...

The stock L29 heads will clear the lift on a Zz502 cam, but that’s about max. When I had my heads redone, I had the guy take .100” off the guides and install positive lock seals and he said it will clear .650 lift now. I also had them install rotator eliminators and 454HO dual springs to go with the cam regrind. The L29 heads flow as well as any BBC head but they are all done by about .500 lift. From .500 to .600 is almost the same flow and the stock truck intake will only support about 450hp and is all done by 4500-5k rpm.

 

[Catbox]

OK. I'll check Bextreme04 for max valve lift with stock Vortec Heads.
The ZZ502 you posted: Lift with 1.7:1 rocker ratio (intake/exhaust) is 527/544.

...sounds good. The ZZ502 is carbureted, and uses Chevrolet Performance Aluminum Bowtie heads. It's not rated for a computer controller though.

I'm not certain you could run it on Cast Iron heads... or if I want to ditch the computer at over a mile high elevation.

Good info...

I should also state that I am not going to be using the stock injection set up.

Mine will wear a Holley carb and a Performer RPM intake under the hood of my truck.