Anyone been able to nail down some specs for Mark IV 454 engines?

[shiftpro]

No need to stud the block. Just buy good bolts, read the instructions and pre-stretch them.
Again, your engine builder is your friend.

 

[bucket]

Well... a little yes. But the mods you mentioned would make much more of a positive improvement with some compression behind it all.
Also, depends on the heads... crappy low compression and low flowing heads will not 'wake up' with cam and exhaust work as much as something that flows... like 781s or 049s like he has.
Not trying to start an argument bucket, just pointing out how these mods don't do the same for every engine.

I agree that some combos will see more improvement, no argument there. But even with a low output, peanut port motor, my statement holds true. The stock intake and cam really suck for most of the truck years.

 

[Mr_Ryumaru]

Have you considered the fuel you will use?
Are you interested in perhaps using propane?
Then you can throw serious compression at it.
And a fun bonus will be the tree huggers who will compliment you on your vintage truck with clean propane...heh heh... not knowing you have 450hp.

To all of your responses, in order lol.

1. Tread lightly , my baby is an '83 Ranger, and that truck is my heart and soul. All manufacturers make good vehicles. All manufacturers make bad ones. All of them have great fans. All of them have idiots.

2. I think the point he was making was that even with low compression, they would still make a noticeable difference. But of course, the best option would be picking up some pistons that will take advantage of the heads/mods.

3. ~$150 was just the first set I had noticed, and had mistakenly assumed that was the price of one piston. After a couple of searches, I will actually be looking in the ~$250 dollar area.

4. I do not have a machinist as that's money I don't have, and I'm doing this build all on my lonesome. As for resurfacing the engine, there's no need. It had been rebuilt less that 5k miles before it was parked. It was parked because it was smoking like a chimney. The cause was not a failure, but rather the meth heads who built it (Not a joke, they were legit meth heads) installed the piston rings without offsetting the gaps. In fact, the gaps were lined up perfectly hence the black hole of a piston pictured above. Also, while I'm just your average guy, the engine was looked over by professionals and deemed to be in outstanding condition, albeit a bit dirty. As for throwing the pistons out, I won't until the new pistons (if I find some) are installed. Even then, I'll likely clean them up and sell them. And lastly, as for valve size, it's one of the things I intend to ask Lunati about and see what they recommend along with the rest of the valve train, in order to best take advantage of their cam I'll be using. There's every chance they might tell me stock size is fine, as this build is going be very mild in nature and going bigger may not be justified. Other than swapping out parts, I have no intention or need really to machine, port, or in any way alter the block/heads. Just swapping better parts in

5. That's simply not practical in my case. This build is going to be my new daily, operated every day living a life split between work, play, and pleasure. In addition, here in Montana we face extreme temperature fluctuations, often times over 60 degrees in one day, easily. On average the summers are 90 degrees or more, and the winter sees -20 regularly, and often much much colder. Especially up in the mountains, where this thing may very well end up due to it also being a plow truck in the winter. Given all of these factors, gas is the most logical fuel, and I have no intention or interest in going with anything else. And to your final point, I'm not concerned with trying to make a lot of power, just a reliable, strong workhorse.

Phew, that was a lot Thanks though, you had a lot of interesting points, and things that made me think. Especially going with an alternative fuel. Even though I won't, its fun to wonder, ya know? And the general consensus seems to be pick up some better pistons, and give the valve train some thought and care, which I will definitely be doing.

 

[Mr_Ryumaru]

No need to stud the block. Just buy good bolts, read the instructions and pre-stretch them.
Again, your engine builder is your friend.

I am the engine builder Can't afford anyone else to do it for me. And I know the studs aren't necessary, but its a trivial cost increase, and offers no downsides.

 

[Mr_Ryumaru]

I agree that some combos will see more improvement, no argument there. But even with a low output, peanut port motor, my statement holds true. The stock intake and cam really suck for most of the truck years.

Oh god the stock intake, I still have mine just in case and tbh I am legitimately dumbfounded as to how they managed even the underwhelming 230hp. I'm just glad my heads are pretty okay, or so I'm told anyways lol

 

[shiftpro]

I agree that some combos will see more improvement, no argument there. But even with a low output, peanut port motor, my statement holds true. The stock intake and cam really suck for most of the truck years.

Yeah I just like to advise on the side of caution, so people don't get disappointed expecting too much.

Cam for sure is a joke, most years as you said. Stock intake... you mean the 4 barrel dual plane? Gosh the thing is simply cavernous. I never thought it would make much difference. I've never been around an intake change on a BB that didn't get a whole world of other mods plugged into it. I mean, hard to determine what an intake is doing when there's a bigger cam at the very least behind it...
It would be fun to do 'one mod at a time' to determine what does what... like in Engine Masters.

 

[Mr_Ryumaru]

Yeah I just like to advise on the side of caution, so people don't get disappointed expecting too much.

Cam for sure is a joke, most years as you said. Stock intake... you mean the 4 barrel dual plane? Gosh the thing is simply cavernous. I never thought it would make much difference. I've never been around an intake change on a BB that didn't get a whole world of other mods plugged into it. I mean, hard to determine what an intake is doing when there's a bigger cam at the very least behind it...
It would be fun to do 'one mod at a time' to determine what does what... like in Engine Masters.

Not sure which stock intakes you've seen, but the one I have is pretty bad. It's restrictive, as well as overly convoluted. I have driven a friends 454 truck before and after he had done an intake swap, and while the difference wasn't huge, the high end power while out on the highway was noticeably better. I know that choice of intake dictates where you'll see the performance gains, but it does show just an intake swap alone can make a difference you can feel.

 

[75gmck25]

Most engines of this vintage are very low compression (around 8.0), so anything you can do to raise compression up to about 9.5 would be a good choice. That will still run fine on 87-89 octane gas. Those flat top pistons may already help raise compression, and you should be able to use a little thinner head gasket to get another .2 compression. Every bit helps.

Once you get compression up, then pick a cam that is designed for a flat torque curve, and suited for a truck or RV. On an SBC that would be in the range of no more than about 218-220 @ .050, and I'm sure someone can advise you on the equivalent duration for a BBC.

The Lunati cam you mentioned in your first post would work fine, but you might be able to use more cam on a BBC if you can get the compression up. Do not get carried away with the cam duration just because the specs say it has a high horsepower potential. You want torque, and you want it to come in early.

A good aluminum dual plane intake should also help quite a bit, along with a carburetor that will flow enough to keep up - at least 750-850 CFM. Then add headers and dual exhaust pipes as big as you can fit. For a BBC I would consider 2 1/2" exhaust as a minimum, and you need low restriction mufflers.

Also check the distributor curve to make sure the mechanical advance comes in quickly (for power), and that the vacuum advance works (for economy).

Bruce

 

[bucket]

Yeah I just like to advise on the side of caution, so people don't get disappointed expecting too much.

Cam for sure is a joke, most years as you said. Stock intake... you mean the 4 barrel dual plane? Gosh the thing is simply cavernous. I never thought it would make much difference. I've never been around an intake change on a BB that didn't get a whole world of other mods plugged into it. I mean, hard to determine what an intake is doing when there's a bigger cam at the very least behind it...
It would be fun to do 'one mod at a time' to determine what does what... like in Engine Masters.

A while back I replaced the stock intake on my '79 dually. It's got peanut ports but the engine has been overhauled by the PO and is supposed to have a very mild "RV" cam of some kind. Anyway, the only changes I made was the intake and a new distributor/wires. The 'ol ass dyno says there was a bit of improvement in the mid-range. Top end should be improved too, but I'm still running a carb that is too small.

My vapor lock issues went away too, getting the carb elevated a few inches and mounted to aluminum. The intake is an older Weiand unit for peanut ports.

 

[Mr_Ryumaru]

Most engines of this vintage are very low compression (around 8.0), so anything you can do to raise compression up to about 9.5 would be a good choice. That will still run fine on 87-89 octane gas. Those flat top pistons may already help raise compression, and you should be able to use a little thinner head gasket to get another .2 compression. Every bit helps.

Once you get compression up, then pick a cam that is designed for a flat torque curve, and suited for a truck or RV. On an SBC that would be in the range of no more than about 218-220 @ .050, and I'm sure someone can advise you on the equivalent duration for a BBC.

The Lunati cam you mentioned in your first post would work fine, but you might be able to use more cam on a BBC if you can get the compression up. Do not get carried away with the cam duration just because the specs say it has a high horsepower potential. You want torque, and you want it to come in early.

A good aluminum dual plane intake should also help quite a bit, along with a carburetor that will flow enough to keep up - at least 750-850 CFM. Then add headers and dual exhaust pipes as big as you can fit. For a BBC I would consider 2 1/2" exhaust as a minimum, and you need low restriction mufflers.

Also check the distributor curve to make sure the mechanical advance comes in quickly (for power), and that the vacuum advance works (for economy).

Bruce

That's been the general opinion, and that's what I'm trying to do. I know I could get away with more cam, but I think the one I've selected is a great middle ground. I'm also a freak apparently because I want a smooth idle :/ I've actually made another thread here, where I'm looking for advice on pistons: https://www.gmsquarebody.com/thread...doesnt-know-his-heads-from-his-asphalt.23543/

As for the intake/carb and exhaust, that's exactly what I had in mind And for the timing curve, when it comes time and more parts are actually installed, I intend to come back here to see what others say. Timing is something I'm still a bit apprehensive of.

A while back I replaced the stock intake on my '79 dually. It's got peanut ports but the engine has been overhauled by the PO and is supposed to have a very mild "RV" cam of some kind. Anyway, the only changes I made was the intake and a new distributor/wires. The 'ol ass dyno says there was a bit of improvement in the mid-range. Top end should be improved too, but I'm still running a carb that is too small.

My vapor lock issues went away too, getting the carb elevated a few inches and mounted to aluminum. The intake is an older Weiand unit for peanut ports.

Like I said, not sure what intakes he's seen, but mine is pretty bad xD

 

[QBuff02]

Aaaaaaaaaaaaaand once again, I'm an idiot. the price of ~150 was for a set of eight, so **** it, why not. You got a link to or part number for yours, just so I can get an idea of what to look for?

I used speedpro L2465F pistons in my 454, it's also .060 over, with -.010 deck height and .040 gasket thickness with 115ish cc chambers I netted a little over 10:1 compression.

 

[4WDKC]

before you get to carried away get the block to a trusted machine shop and have them clean up the bores, this will tell you if you need to buy new pistons or not.

 

[nvrenuf]

I agree ^^

Don't invest a lot in it until you're sure the big parts are good.

 

[Mr_Ryumaru]

before you get to carried away get the block to a trusted machine shop and have them clean up the bores, this will tell you if you need to buy new pistons or not.

I agree ^^

Don't invest a lot in it until you're sure the big parts are good.

As said earlier in the thread (a few times ), the block was already looked over by someone, was deemed to be in excellent condition. It doesn't even need to be bored, just honed up a bit. No ridge, no cracks, all good. Motor had less than 5k miles on it since it was rebuilt. It was pulled apart due to profuse smoke out the exhaust, which ended up being caused by improperly installed piston rings (they didn't offset the gaps). I do not need new pistons, the ones I have are in great shape. But I have no issue justifying $250 bucks added in cost for better pistons that will help the motor perform better. I will keep these ones for now, until I get new ones. I will most likely have the rotating assembly tested for balance at that point. If everything goes well, I'll just clean the old pistons up and sell them.

 

[4WDKC]

As said earlier in the thread (a few times ), the block was already looked over by someone, was deemed to be in excellent condition. It doesn't even need to be bored, just honed up a bit. No ridge, no cracks, all good. Motor had less than 5k miles on it since it was rebuilt. It was pulled apart due to profuse smoke out the exhaust, which ended up being caused by improperly installed piston rings (they didn't offset the gaps). I do not need new pistons, the ones I have are in great shape. But I have no issue justifying $250 bucks added in cost for better pistons that will help the motor perform better. I will keep these ones for now, until I get new ones. I will most likely have the rotating assembly tested for balance at that point. If everything goes well, I'll just clean the old pistons up and sell them.

I thought the rust looked worse than was mentioned.