The Official Vortec 454 Info thread

[yevgenievich]

Hi, new here. I apologise in advanced for a long post. I joined this forum just for this thread! Awesome info and I have a ton of reading to get caught up. I have a 97 K3500 extended cab dually with 232,000 hard miles on the original 7.4l engine. It has the usual problems - leaks, down on power, hard hot starts. I decided to buy a second engine to build up and swap in. After a few calls on craigslist, I found a complete 99 7.4 from a rolled suburban with 30,000 miles, in storage for 15 years, and got it for $1,200.

I took it apart to see how good it was and to replace the seals if nothing else. It was in fact very low miles, but there was strange, spotty wear on the main and rod bearings that I can't figure out, like maybe metal particles or chips were caught under the bearings at the factory. I can't leave anything alone, so that was all I needed to go off. I decided to do a light hone and re-ring with the stock pistons, get the crank reground, the rods resized, do some port and chamber work, then throw in a cam, springs, and adjustable roller rockers.

The crank counterweights were nicked and dinged like it spent an hour in a cement mixer, so I deburred and polished it and bullnosed the leading edges with a disk sander and DA sander. I deburred the block inside and out, then took it to my engine shop. The block was decked 0.010 to square it up (.003" unsquare to the crank on one bank), then torque-plate honed. This alone will improve power and mileage, as the stock hone was obviously not done with torque plates. Torque plates reproduce bore distortion resulting from bolt tension when the heads are on. A few passes of the sunnen hone revealed dimples, or low spots in the bores due to the bolt load. About 15 strokes in each bore were needed to make them clean and round, which added .001-.0015 to the bore diameter. This will increase piston clearance and require a file-fit ring set, but otherwise won't hurt anything.

My shop supplied a Sealed Power 4.250 +.005 ring set, which needed a lot of material ground off. I got tired of spinning the ring filer by hand, so I turned it's shaft down until I could get it in a drill. I set the top rings at .018" and the second at .010. I soon discovered that the stock pistons have a shallow oil ring groove for low tension rings, but the ring set came with conventional Mk4 style oil rings. I got the right oil ring set from Total Seal for another $76.

Everything went right together after that, with ARP rod nuts on stock rod bolts. The pistons measured .014-.015 below deck, so they were a full .025 below before the deck was cut. I am surprised by that. That gap is dead space that can't be scavenged, which hurts mileage and increases emissions, so why would the OEM do it? To reduce compression? They should know better. I will be doing some cutting and polishing on the chambers that will increase chamber volume, so the deck cut will help bring back any lost compression.

For a cam, I had my eye on a Comp Cams XR258HR for a long time now. It's pretty mild, but my truck is used almost entirely for towing race trailers. So I ordered one on the website because it said they would be in stock in 2 weeks. Then I got an email saying they are really out of stock for 3-6 months due to a nationwide cam core shortage. Oh well, $380 order cancelled.

For a better solution I sent the stock cam up to Delta Cam grinding in Washington state. It came back today, 10 days and $135 later. They reground it to the more aggressive Comp XR profile, but with some custom twists. The intake now has 206° duration at .050 with .510 valve lift, the exhaust 210° with .522 lift. I requested a lobe separation angle of 112° to go between the standard performance angle of 110, and the typical 'computer controlled' angle of 114. It was also ground with 4° advance built in (stock is 6° retarded, which IS retarded). Regrinding reduced the base circle diameter by about .050, which may require custom pushrods, but that's no problem. It's also getting a Comp 3149KT timing set, 911 valve springs, 1411 rocker arms, 4514 rocker studs, and 4779 spring locator cups that eliminate the rotators.

There is a ton of other stuff to figure out. I want to add better injectors and a firewall mounted fuel regulator, and maybe a bigger throttle body. I'm adding headers and I have some big ideas to improve the intake manifold, so it will no doubt need a tune. I may need the 0411 ecm swap too. I will be reading and asking you guys for tips and links, and post some pics the build so far tomorrow.

interested in intake improvements ideas, slowly building a replacement for my burb as well.

 

[SS Performance]

I would look at a turbo.

I have some experience with turbos. I my experience they are better at higher RPM power than low end torque which is what I am looking for,

Edelbrock 60499 Edelbrock Performer Cylinder Heads | Summit Racing

Free Shipping - Edelbrock Performer Cylinder Heads with qualifying orders of $109. Shop Cylinder Heads at Summit Racing.

www.summitracing.com

www.summitracing.com/parts/edl-60499

I was under the impression they had 110cc chambers, definitely worth a look.

Thanks for the responses.

Craig

 

[SS Performance]

Any suggestions on headers?

 

[Supercharged111]

I have some experience with turbos. I my experience they are better at higher RPM power than low end torque which is what I am looking for,

I was under the impression they had 110cc chambers, definitely worth a look.

Thanks for the responses.

Craig

They are, but I hit 2000 RPM before 55mph. That's plenty to have 10# brewed up.

 

[Schurkey]

I have some experience with turbos. I my experience they are better at higher RPM power than low end torque which is what I am looking for,

Depends on how they're set up.

There's a whole world of low-rpm turbo diesels out there.

 

[Mangonesailor]

Lots o' words....

There is a ton of other stuff to figure out. I want to add better injectors and a firewall mounted fuel regulator,

Feel free to poke my brain about 0411 stuff. I used to have a standard PM I liked to send guys once they swapped a 0411. Lextech is the way to go for the package, but there are some things I like to personally point out after the fact.

In any case, let us know how that valve train stacks up under factory valve covers. Some R&D on a 454 Gen VI was something I really wanted to do years ago for the community, but unfortunately I changed jobs and couldn't really fund it. In return though I have a family and a real life I wouldn't trade for anything, so I do what I can and try to pass on what I learned.

If you're interested in my parts list I'd made for myself to fit an aftermarket FPR to the factory fuel lines let me know. Takes a little work but it lessens any messing with the fuel rail (Honestly I wish someone made an aluminum one already but there's no market for that you know).

Know what your new compression ratio is after the decking?

 

[Scottm]

Feel free to poke my brain about 0411 stuff. I used to have a standard PM I liked to send guys once they swapped a 0411. Lextech is the way to go for the package, but there are some things I like to personally point out after the fact.

In any case, let us know how that valve train stacks up under factory valve covers. Some R&D on a 454 Gen VI was something I really wanted to do years ago for the community, but unfortunately I changed jobs and couldn't really fund it. In return though I have a family and a real life I wouldn't trade for anything, so I do what I can and try to pass on what I learned.

If you're interested in my parts list I'd made for myself to fit an aftermarket FPR to the factory fuel lines let me know. Takes a little work but it lessens any messing with the fuel rail (Honestly I wish someone made an aluminum one already but there's no market for that you know).

Know what your new compression ratio is after the decking?

Thanks! I will. The compression ratio stock is allegedly 9.1. I won't know my new ratio until I cc the chambers after some grinding and polishing, and determine the thickness of my new head gaskets. I figure some bowl work will increase volume a few cc's which will probably offset any compression gain from the reduced deck height.

So another option for induction is a Holley Sniper with a performer intake. It will cost more of course, but has major advantages. My reservation is passing emissions. Snipers are supposedly 50 state legal. 1 ton trucks are sniff-tested on the chassis dyno, and a healthy engine will easily pass, but AZ also has an under hood inspection. My engine needs egr, pvc, and vapor recovery. I could rig all that up to the performer/sniper, but will it fail just for not being stock? If I paint it black, the average tech probably won't even notice.

Here are some pics - full-race ring grinder, reground cam, pistons marked with their height below deck, a baked and shot-blast cleaned head. There is a sharpy mark showing where I'm going to relieve the chambers to improve exhaust flow out. The screwdriver is pointing to the 'swirl enhancing' lump in the intake valve pockets. I don't know what to do with those lumps. David Vizard the head porting expert has vids on youtube showing how to port 350 vortecs with similar lumps, but big block heads are different.

BB intake runners are not symmetrical or mirror-image. There are two different shaped ports, called the short and the long. They don't flow the same, and that is the single biggest reason why chevy big blocks are not very efficient. Half the cylinders are stronger, and their extra power is wasted motoring the weaker. A 427 conventional small block will make more torque, hp, and get better mileage than a bb 427, and weigh 200 pounds less. People have been trying for over 50 years to make them flow equally. Have you ever seen pics of old mechanical fuel injection with two different length intake stacks? They are trying to compensate for the different head ports. Chevy finally fixed it with the heads on the 8.1 vortec. They look like LS heads with identical ports. The 8.1 actually has tremendous potential, but you have to go to Raylar engineering to unlock it. I wonder if 8.1 heads will fit the 7.4?

Vortec 8100 8.1L Gen 7 Big Block Chevy CNC Aluminum Cylinder Heads - 496cid Performance Cylinder Heads - Raylar Engineering

Vortec 8100 8.1L 496cid performance cnc aluminum cylinder heads. Raylar Big Power cylinder heads for the Vortec 8100 8.1L 496 engine boost power and economy.

www.raylarengineering.com

Anyway, the approach to working the bowls and swirl lumps will vary with the long and short ports, and that info is what I'm looking for. It doesn't matter much on low rpm truck engines, but it still bugs me.

 

[Schurkey]

I wonder if 8.1 heads will fit the 7.4?

Yes...depending on whether you've got enough money to pay a machine shop to plug and re-drill three head bolt holes in the block on each deck. Moving six head bolt holes altogether. They're not moved very far--that's part of the problem. You're only moving one hole about half the bolt diameter; so it's gonna be tricky to plug the hole, then partially drill the plug so it can be tapped.

Chevy actually did this on a project vehicle. It may be that they grabbed a block off the production line before the head bolt holes were drilled and tapped, so that they could put them in the correct place for the 8.1L cylinder head.

 

[smokymtn65]

Feel free to poke my brain about 0411 stuff. I used to have a standard PM I liked to send guys once they swapped a 0411. Lextech is the way to go for the package, but there are some things I like to personally point out after the fact.

In any case, let us know how that valve train stacks up under factory valve covers. Some R&D on a 454 Gen VI was something I really wanted to do years ago for the community, but unfortunately I changed jobs and couldn't really fund it. In return though I have a family and a real life I wouldn't trade for anything, so I do what I can and try to pass on what I learned.

If you're interested in my parts list I'd made for myself to fit an aftermarket FPR to the factory fuel lines let me know. Takes a little work but it lessens any messing with the fuel rail (Honestly I wish someone made an aluminum one already but there's no market for that you know).

Know what your new compression ratio is after the decking?

Might hit you up too. I have the 0411 and two sets of plugs , (to build a bench flash setup) and have the pin out from Lextech, but that is as far as I have gotten, going to need to flash the 8.1 to the 0411 or if someone has a file that will work closer to my needs that will be awesome too!

 

[Scottm]

Yes...depending on whether you've got enough money to pay a machine shop to plug and re-drill three head bolt holes in the block on each deck. Moving six head bolt holes altogether. They're not moved very far--that's part of the problem. You're only moving one hole about half the bolt diameter; so it's gonna be tricky to plug the hole, then partially drill the plug so it can be tapped.

Chevy actually did this on a project vehicle. It may be that they grabbed a block off the production line before the head bolt holes were drilled and tapped, so that they could put them in the correct place for the 8.1L cylinder head.

Awesome! That makes perfect sense. Just looking at the bolt pattern in the block you can see the space between holes varies. Look at my 4th picture from yesterday - there are no bolt holes above cylinders 2 and 6. Redrilling is doable for me as I have a bridgeport mill. I would put low strength all-thread pieces into the block with green loctite, then mill the new holes with a mill bit, as mill bits won't deflect when cutting the harder of the two materials. I'm not going to do it on this build, but ill keep the info in mind.