454 BBC engine build

[Cthibo500]

truck: 81 2wd stepside
engine: 454 out of 78 suburban.
did a tear down everything looked normal, nothing crazy
i'm curious as to how to figure out home much compression i'd be running if/when I decide to go with this rotating assembly

http://www.summitracing.com/parts/sc...05bi/overview/

with these heads

http://www.ebay.com/itm/230838635537...537%26_rdc%3D1

i'm thinking thats going to be way to high of a CR to run on pump gas (91/93)

If its too high i was thinking about going with this set up for a RA

http://www.summitracing.com/parts/sc...05bi/overview/

[Cthibo500]

in case anyone would wonder what i was going to run for a cam

http://www.summitracing.com/parts/cca-sk11-208-3

[funkatation]

I went with flat tops on mine. I had a little work done to my 781 heads and zero decked the block. We ended up at 9.4:1.
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[68c10owner]

You should be ok on 91 pump gas but that cam is going to be really mild in a 489. I wouldn't waste the money on aftermarket heads with such a mild build. Find some 049 or 781 heads and run some 2.19/1.88 valves with a little bowl work and be done. I'd also go with a little more camshaft, roller if possible and look for something g with at least a 10-12 degree split if using OEM style heads. Look into the voodoo line if you want a shelf cam.

[funkatation]

I put this cam in my 489: http://m.summitracing.com/parts/lun-20110711
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[Jake Wade]

I don't know your exact deck height but, safe to say your CR will be in the 9.9:1 range, not a problem with aluminum heads.

I would be leary about those heads, you cannot buy ONE Brodix, AFR, Dart, etc for that price. Chinese for sure, some of the Chinese castings can be made into pretty decent heads, just Beware.

You didn't say what the intended usage was but, 320cc rectangular ports are pretty big, even for a 489, especially if your focus is on low end torque.

[funkatation]

I can safely say I will never buy another speed master / pro comp part ever again. I bought a serpentine kit that was a cheap knock off and poorly designed so sent it back. I also bought an oil pan and it leaked from a weld. Talk about disappointed. You get what you pay for. I looked at those heads and decided to stick with my 781s.
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[Jake Wade]

http://www.aeroheadracing.com/chevy.html

Scroll down and you will find some good ole GM oval ports ready to go for $895

I have bought heads from these folks before.

[Cthibo500]

Pretty much mostly street/DD but I'm looking for enough power for cruise nights and messing around.
Transmission is a T56 6 speed, rear gear is a 3.73 with a 30 inch tall rear tire.

[nvrenuf]

Originally Posted by funkatation

I put this cam in my 489: http://m.summitracing.com/parts/lun-20110711
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What's your review of this cam? I've been staring at that one with regret ever since building my 454 with a smaller comp cam. Any video of your truck online?

[68c10owner]

Originally Posted by Cthibo500

Pretty much mostly street/DD but I'm looking for enough power for cruise nights and messing around.
Transmission is a T56 6 speed, rear gear is a 3.73 with a 30 inch tall rear tire.

Stick with a OEM oval port and run a modern cam. I'd go with a hydraulic roller if you can afford it. This one will make all the torque you can handle

http://www.speedwaymotors.com/Clay-S...454,80449.html

[pistonbroke800]

Stick with that first rotating assembly but ditch those heads and that cam is way too small for a stroker big block. As others have said and I built my 496 the same way. 781 heads and a cam similar to the one Funkatation recommended. Mine is a touch bigger not by a lot and its a real power house of an engine.

[Cthibo500]

I wasn't PLANNING on doing a mild build. checked out aerohead website with a friend (who also has a 489) and after the negative reviews i've seen here and from other sources. Scrapped the idea of those aluminum procomps, and go with a build iron set from them. Change the cam to http://www.summitracing.com/parts/cc...make/chevrolet for a little more lift.
New to the big block world... obviously

[68c10owner]

Originally Posted by Cthibo500

I wasn't PLANNING on doing a mild build. checked out aerohead website with a friend (who also has a 489) and after the negative reviews i've seen here and from other sources. Scrapped the idea of those aluminum procomps, and go with a build iron set from them. Change the cam to http://www.summitracing.com/parts/cc...make/chevrolet for a little more lift.
New to the big block world... obviously

You are money ahead to go with a roller cam. If you are stuck with a flat tappet cam look into the voodoo grinds from lunati. You will want a split pattern camshaft with OEM heads and the comp magnum grinds are really a old school cam. They will make decent power but you really want a modern grind. If you are stuck on comp cams look at the extreme line.

[Jake Wade]

My advise would be to forget about running a flat tappet. Save your money, do whatever you have to do to spend the extra coin and go hydraulic roller, yeah, its going to cost you a bunch more but, do it once and forget about it.

This is a proven winner in big blocks with GM oval ports:

http://www.claysmithcams.com/bbc-454...x-of-5700-rpm/

[Firebirdjones]

I'll second the Voodoo grinds from Lunati. Howard was behind the design of those cams and they work fantastic.

However, I'd wait until you know exactly where your compression is going to be before I made any camshaft selections. Lobe sep and duration are going to play a huge roll with compression and how the engine is going to respond.

Sounds like you'll be hitting a machine shop, and hopefully a good one. Any good shop should be able to calculate where your compression is going to fall. (don't rely on what a rotating assembly says, that's a ball park) Cylinder heads vary on chamber sizes, deck heights, piston pin heights, will all change compression. From there a good shop that specs a lot of custom grinds can taylor the camshaft that would work best for the combo, rather than an off the shelf cam. I only use "shelf" cams about 10% of the time. I prefer rollers nowadays as well, but still build flat tappets in certain cars for various reasons.

[68c10owner]

Originally Posted by Firebirdjones

I'll second the Voodoo grinds from Lunati. Howard was behind the design of those cams and they work fantastic.

However, I'd wait until you know exactly where your compression is going to be before I made any camshaft selections. Lobe sep and duration are going to play a huge roll with compression and how the engine is going to respond.

Sounds like you'll be hitting a machine shop, and hopefully a good one. Any good shop should be able to calculate where your compression is going to fall. (don't rely on what a rotating assembly says, that's a ball park) Cylinder heads vary on chamber sizes, deck heights, piston pin heights, will all change compression. From there a good shop that specs a lot of custom grinds can taylor the camshaft that would work best for the combo, rather than an off the shelf cam. I only use "shelf" cams about 10% of the time. I prefer rollers nowadays as well, but still build flat tappets in certain cars for various reasons.

Harold Brookshire designed the Lunati Voodoo grinds. I wouldn't be so much worried about the compression as picking the ca.camshaft for the correct rpm range. The camshaft Jake and I linked to was designed bt Chris Straub and will make all kinds of power with stock heads.

[Firebirdjones]

Harold is what I meant, sorry, I called him Howard all the time He's gone and I still find myself doing that.

Compression is just as important if not more so than rpm range, and just as much as cylinder head selection. "Correct" rpm range is somewhat subjective, and a grey area considering so many variables. If this guy wants to run pump gas I'd be more concerned with the intake valve events and LSA so as to work well with the compression ratio they are shooting for. It's a fine line, and usually something that an off the shelf cam with modern lobes doesn't favor as much.
Too much one way or the other with a cam that doesn't like it is either going to make a pooch of an engine or one that is so sensitive to gas you're going to hate driving it.
For example, with an iron head on pump gas, and considering he's running a stick shift, I wouldn't want a 109 lsa.

[68c10owner]

Originally Posted by Firebirdjones

Harold is what I meant, sorry, I called him Howard all the time He's gone and I still find myself doing that.

Compression is just as important if not more so than rpm range, and just as much as cylinder head selection. "Correct" rpm range is somewhat subjective, and a grey area considering so many variables. If this guy wants to run pump gas I'd be more concerned with the intake valve events and LSA so as to work well with the compression ratio they are shooting for. It's a fine line, and usually something that an off the shelf cam with modern lobes doesn't favor as much.
Too much one way or the other with a cam that doesn't like it is either going to make a pooch of an engine or one that is so sensitive to gas you're going to hate driving it.

Cylinder head and rpm range is more important than compression. Compression isn't as important as the cam timing can be adjusted to make cylinder pressure, if using using a custom grind camshft. Shelf grinds it does effect the DCR.

[Firebirdjones]

Um....okay if you want to bandaid a bad cam choice by moving the camshaft position around because the compression isn't ideal for the valve events that's fine, but it's not how most do it.

The whole point I'm making, is to taylor the compression and cam together so it makes cylinder pressure at the right time without creating a serious detonation issue on pump gas. All your experienced and high end engine builders pay close attention to this. But if that's not important to you.....

If you create a rattle trap with too much compression for a given intake valve event creating more cylinder pressure down low, retarding the cam may or may not help the issue, and in every case I've seen on the dyno, retarding the cam does nothing but hurt power across the board. Engine becomes a pooch. I see people back themselves into this corner quite often. Especially out West here where we only have 91 octane.

[68c10owner]

Originally Posted by Firebirdjones

Um....okay if you want to bandaid a bad cam choice by moving the camshaft position around because the compression isn't ideal for the valve events that's fine, but it's not how most do it.

The whole point I'm making, is to taylor the compression and cam together so it makes cylinder pressure at the right time without creating a serious detonation issue on pump gas. All your experienced and high end engine builders pay close attention to this. But if that's not important to you.....

If you create a rattle trap with too much compression for a given intake valve event creating more cylinder pressure down low, retarding the cam may or may not help the issue, and in every case I've seen on the dyno, retarding the cam does nothing but hurt power across the board. Engine becomes a pooch. I see people back themselves into this corner quite often. Especially out West here where we only have 91 octane.

Yeah I'm not talking about the ICL or intake centerline which has to do with advancing or retarding he cam. I'm talking about the actual degree in which the valve opens and closes, cam timing. With a shelf grind you really have no options but if you have one custom ground you can taylor the opening and closing events to boost cylinder pressure on a low static compression engine. Professional engine builders know this, trust me. People get themselves into trouble because they don't understand cam timing and how it effects the DCR or dynamic compressing ratio. Even that isn't important to most professional engine builders as the numbers can be manipulated. They will tell you knowing what cylinder head is used and what it flows and what rpm the customer what's to make the power is more important than the static compression. I've seen 8:1 bbc's run just as hard as some 10-11:1 engines. Compression makes power sure, but with a custom designed camshaft the static compression is not the first question asked.

Tell me something, what is the camshft doing on the compression stroke?

[Cthibo500]

It's going to a well respected and reputable machine shop in my area. Which I'm assuming Noone knows but is pretty remote. Not many machine shops. Haven't really done any readers In a custom grind or anything. I was just originally concerned with the CR with those heads and rotating assembly set up with flats or domes. Kinda made up my mind on a flat set up. My rpm range is 2000 to aprox 6k. Im not talking about all the power between that, I'd just like to hit that 6k on the tach AFTER a year of break in. Just dont want something that completely falls on its face after 5k
I do plan on babying it the first summer.

[68c10owner]

Originally Posted by Cthibo500

It's going to a well respected and reputable machine shop in my area. Which I'm assuming Noone knows but is pretty remote. Not many machine shops. Haven't really done any readers In a custom grind or anything. I was just originally concerned with the CR with those heads and rotating assembly set up with flats or domes. Kinda made up my mind on a flat set up. My rpm range is 2000 to aprox 6k. Im not talking about all the power between that, I'd just like to hit that 6k on the tach AFTER a year of break in. Just dont want something that completely falls on its face after 5k
I do plan on babying it the first summer.

That clay smith cam with some cleaned up big ovals will make plenty of power in that rpm range. Google Chris Straub. He designed those grinds for Clay Smith. Talk to him about it. You won't be disappointed if you ran that cam, even with the flat tops.

As for break in, never baby it. If you use a flat tappet cam, break the camshaft in, run it around the neighborhood to make sure of no leaks and oil psi and water temp is good, going through the gears a little. Once you decide all is good, drive it how your going to drive it. The only engine I had that failed was babied. After I rebuilt it the builder who is still at the same shop after about 40yrs gave me that advice and it's never let me down since.