Another 489bbc question

[Blue Rat]

I think I would run with the 10.5-11.1 CR. Get the 270cc or equivalent head. Stay away from the cheaper heads. Go with the 119 cc head. The 270cc race rites come with the 2.25 an 1.88's. If the price scare you take a look at these prices https://www.airflowresearch.com/ here. Hyd. roller would work to around 6500 or so. But if you go solid roller you are not going much over 6500.

[68c10owner]

Originally Posted by Blue Rat

I think I would run with the 10.5-11.1 CR. Get the 270cc or equivalent head. Stay away from the cheaper heads. Go with the 119 cc head. The 270cc race rites come with the 2.25 an 1.88's. If the price scare you take a look at these prices https://www.airflowresearch.com/ here. Hyd. roller would work to around 6500 or so. But if you go solid roller you are not going much over 6500.

The AFR heads are more expencive but either the AFR or the Brodix are great heads that will make plenty of power. If you shop around you can find the Brodix heads a little cheaper.

Contact Chris Straub or this guy about the heads,

http://www.lewisracingengines.com/

Mike Lewis can order them with whatever spring you need for whatever cam your going to run. I would stick with a hydraulic roller. Go for low-mid range torque to get the heavy truck moving so I wouldnt think you would see 6500rpms much.

[70shortwide]

I know people are down on procomp heads (i dont know why???) but I ran them with no problems and made awesome power I probably would have been close to 11.0's with some more tuning if the rod hadnt decided to let go

[Kyle@FTP]

Originally Posted by 68c10owner

The AFR heads are more expencive but either the AFR or the Brodix are great heads that will make plenty of power. If you shop around you can find the Brodix heads a little cheaper.

Contact Chris Straub or this guy about the heads,

http://www.lewisracingengines.com/

Mike Lewis can order them with whatever spring you need for whatever cam your going to run. I would stick with a hydraulic roller. Go for low-mid range torque to get the heavy truck moving so I wouldnt think you would see 6500rpms much.

I think I mentioned the solid roller a few post back and we got off topic to lifter bleed.

I do think a Hyd roller set up will be great for this build. And when it come to the heads just work out the math. How mutch it will cost to have the 781s done correctly to build the power you want vs. what it cost to buy a new set of heads that will make that power.

[Kyle@FTP]

Originally Posted by 70shortwide

I know people are down on procomp heads (i dont know why???) but I ran them with no problems and made awesome power I probably would have been close to 11.0's with some more tuning if the rod hadnt decided to let go

The casting from procomp are a decent enough casting. Where they get the bad reputation is their lack of final assembly skills. If you pull a procomp head apart and check clearenses you will see they vary a lot. For me, They are going in a marine application and sees high RPM for a long time. The procomp heads usually have a tight valve guide clearance. By the time you buy procomps and have them reworked to what I consisder is usable, you might as well buy darts/brodix/canfields/afr

[68c10owner]

Originally Posted by 70shortwide

I know people are down on procomp heads (i dont know why???) but I ran them with no problems and made awesome power I probably would have been close to 11.0's with some more tuning if the rod hadnt decided to let go

First problem is they are a over seas casting. Their idea of quality control is a little different than it is here in the states. I have heard of valve seats falling out, rocker arm stud not located correctly, and severe porosity in the castings. There are going to be success stories but those arent very common. If you use these heads its best to buy them bare and have a good machine shop go through them and set them up. I`d use the oems before using procomps but thats just my opinion.

[Roll'nSlo]

Any opinions on these:

http://m.ebay.com/itm/230838635530

[68c10owner]

Originally Posted by Roll'nSlo

Any opinions on these:

http://m.ebay.com/itm/230838635530

Buy a known brand. Anything you find on eBay that doesn't have a known brand is a gamble and I'd never buy them complete. If you must use off shore heads buy them bare and use good parts to assemble.

[Blue Rat]

Originally Posted by 68c10owner

Buy a known brand. Anything you find on eBay that doesn't have a known brand is a gamble and I'd never buy them complete. If you must use off shore heads buy them bare and use good parts to assemble.

I agree totally with 68c10owner. If you are having a hard time justifying this purchase just start hiding some money back somewhere until you have enough. Besides it might be the angle that the heads are at in the picture. But they look like square ports too me.

[Roll'nSlo]

Originally Posted by Blue Rat

I agree totally with 68c10owner. If you are having a hard time justifying this purchase just start hiding some money back somewhere until you have enough. Besides it might be the angle that the heads are at in the picture. But they look like square ports too me.

I thought the same thing. But they have several listings and list both square and oval with exactly same pics.

Anyways, I'm just trying to find an affordable route. If I could find a good set of heads around $1000 complete I would buy them. Guess I need to just keep shopping and looking. I already did some looking and decided to go the 489 route. Found a Scat crank and bearings for $329, rods for $300(I think) and pistons for $350-500(I think). I'm focusing on heads right now cause they're one of the more expensive items.

[68c10owner]

Had to go back through to see what the plans were for this engine. Ok, so WEEKEND TOY is what I found.

If you want a weekend toy, use your 781`s. Put 2.25/1.88 valves in them, do some bowl work, short turn, gasket match, shape the guide bosses, go to a 11/32 valve to help with the flow and be done. If your going to do the 489 then worry about building torque. Thats what puts you in the seat and thats what we all want in a street car. Plus it will be less finicky to drive around.

Once you get the heads done you can pick your cam. Make sure you get flow numbers because without them you may as well throw darts at the board for cam choice. I`m going to suggest Chris Straub again for the cam because he has a proven record when designing camshafts. Check out this site and look up Cstraub,

http://www.chevelles.com/forums/forumdisplay.php?f=13


A good cast steel crank from Eagle or Scat will be more than you need and is budget friendly. Stick with I-beam rods and I would suggest Scat rods with the capscrew option in either 3//8 or 716 in this case.

Pistons, you need a 18cc dome to get 10:1 with your heads which should be 119cc chambers. SRP or Probe would be good. You might find a Icon piston that works as well. You could even go with a smaller dome for slightly less compression. Bigger engines need less compression to make the power. Here is a good place for a quality, budget friendly rotating assembly,

http://www.coasthigh.com/Chevy-496-e...me-s/13123.htm


I understand what your trying to do. Get some "hi performance" heads at a low cost but the fact of the matter is sometimes the headaches these cheap heads create end up being more than some top end parts were to start with. Build a good solid shortblock now, heads and cam can be changed later on. There are so many guys running 496 engines with 78` heads with the little bit of work I suggested that are very close to the 600hp mark and the same in torque or more. Do some research before buying a bunch of parts. Everything needs to work together. I`m trying to help you the best I can but you know what they say, you can lead a horse to water....

[Roll'nSlo]

But you can't make him drink it.

I appreciate and respect everyone's opinion and advice. That's why I started looking for new heads. And yes it's a weekend toy, I'm not trying to get a 9 second truck. I wish I could though. Haha

I've about came to the same conclusion. I'll get my heads checked out and cut. Just not ported. If I make 600hp I'm happy if not it'll still be stout.

So hyd. roller over solid roller is the best way? I'll Chris a call when I start looking at cams.

[68c10owner]

Unless your spinning it higher than 7000rpms you don't need a solid but you can go solid if you prefer. A hydraulic roller will make very strong power and if you get the good lifters, like from Chris, it will go to 7000rpms. Chris will match you a complete valve train. Just be completely honest about what its being used for, what rpm you want to turn it and what the heads flow.

[Roll'nSlo]

Out of curiosity, can you give me a ballpark of what you think he'll charge.

[68c10owner]

He lists some prices on his site but I believe its around $1500 for the cam on a billet core, lifters, valve springs and pushrods. The catalog cast core roller cams have been known to break with too much spring pressure fans they require a bronze gear unless you order it with a cast gear option for your distributor. The billet cores are much stronger. Give him a call, he should be able to give you a ballpark on HP number too

[Super73]

Different application and valve trane but I run hyd rollers and spins 7,800. But I have a 2.08 valve that weighs around 90g. 165lb on the seat and 465lbs wide open at .630 lift.

[mud.man.rj]

Nice thing about a big block is torque, so stick with the suggestion of 3.73 for gears, won't need to spin it up but will need more stall, at least around 2,500 to 2,700 and may even have to go up to 3,000 with a tunnel ram just to make it streetable, remember the stall actually moves the truck before it's listed stall speed. Tunnel ram will make it look cool but less streetable.

[Roll'nSlo]

But will it help or kill it on performance?

[68c10owner]

Tunnel rams are not less streetable. They are more difficult to tune than a single 4bbl but plenty streetable and usually make more power than a single 4bbl but dont think you`ll want it for a lower rom torque motor. I must have missed this, were you considering a tunnel ram? Stall speed is going to be determined by what camshaft you use. You are going to want to stay in the 2500-2800rpm range for a stall. Dont think you`ll need a 3000 stall. A good quality stall converter will drive like a normal converter from a stop. The foot brake is how much you can give it throttle while holding the brake. Its only going to go so much before you break the tires loose. Rear gear will effect the foot brake. The flash stall speed is what happens when you nail the gas and the rpms jump up to what the flash is. The more torque, the more stall your going to have. If you have a 2500 stall behind a stock 350 and then put a 600hp 496 in front of it you will get more stall.

[Roll'nSlo]

Yes, I was contemplating a tunnel ram. Just not for sure if it would help or not.

[68c10owner]

Originally Posted by Roll'nSlo

Yes, I was contemplating a tunnel ram. Just not for sure if it would help or not.

If your not good at tuning multiple carbs I wouldnt recommend it. Most are designed for high rpms but Edelbrock and Weiand both have "street" versions that will work fine.

[Super73]

Originally Posted by 68c10owner

Tunnel rams are not less streetable. They are more difficult to tune than a single 4bbl but plenty streetable and usually make more power than a single 4bbl but dont think you`ll want it for a lower rom torque motor. I must have missed this, were you considering a tunnel ram? Stall speed is going to be determined by what camshaft you use. You are going to want to stay in the 2500-2800rpm range for a stall. Dont think you`ll need a 3000 stall. A good quality stall converter will drive like a normal converter from a stop. The foot brake is how much you can give it throttle while holding the brake. Its only going to go so much before you break the tires loose. Rear gear will effect the foot brake. The flash stall speed is what happens when you nail the gas and the rpms jump up to what the flash is. The more torque, the more stall your going to have. If you have a 2500 stall behind a stock 350 and then put a 600hp 496 in front of it you will get more stall.

The are more thing than cam that dictate stall speed than just a cam. Intake runner length, rod ratio, header tube length and diameter and more plays a role in to peak tq rpm. Valve events definately have a heavy hand in it but at the end of the day peak tq rpm really dictates where optimal stall speed is.

[68c10owner]

Originally Posted by Super73

The are more thing than cam that dictate stall speed than just a cam. Intake runner length, rod ratio, header tube length and diameter and more plays a role in to peak tq rpm. Valve events definately have a heavy hand in it but at the end of the day peak tq rpm really dictates where optimal stall speed is.

??? The cam is the brain of the engine. How can you say that? Without the cam you dont know what intake runner length you need or header tube size and length. Power band dictates what stall you need and the camshaft is a major player in determining the power band. I should have been more clear on my description but I wasnt wrong.

You have to match the engine. You need to know what RPM you want to turn the engine. Then figure out what heads its going to take to feed the engine with the RPM in mind and what HP your shooting for. Once you know what heads and what RPM only thing left is picking the camshaft. Rod ratio has very little effect on peak power. Then ideally you will dyno the engine to know where the peak power is and pick you converter accordingly.

[Super73]

Sorry, if I was building a motor for a target RPM, the cam is the very last thing in the motor I would figure out not the first.

Stick a large duration/high overlap cam in a motor intended for high rpm, in a motor with a long runner dual plain and a small tube header, Peak TQ rpm is going to change from the large single plain / big tube header is should have. Those valve events are no longer optimal for that runner and header.

I have seen many combo's that the above example applies to. Big cam for high RPM yet choked off by intake and wrong headers. Power band is way earlier than initially thought. Or the opposite, small cam with a single plain and big tube headers, motor can't breath due to the small cam.

Valve events should always be figured out after all the supporting components are selected for intended usage.. As you said, the cam is the brains, if you don't go to school (supporting mods) how can you do your job (cam).

An optimal converter for best performance has to be selected once peak TQ RPM is identified. Otherwise you are only throwing darts.

[68c10owner]

Originally Posted by Super73

Sorry, if I was building a motor for a target RPM, the cam is the very last thing in the motor I would figure out not the first.

Stick a large duration/high overlap cam in a motor intended for high rpm, in a motor with a long runner dual plain and a small tube header, Peak TQ rpm is going to change from the large single plain / big tube header is should have. Those valve events are no longer optimal for that runner and header.

I have seen many combo's that the above example applies to. Big cam for high RPM yet choked off by intake and wrong headers. Power band is way earlier than initially thought. Or the opposite, small cam with a single plain and big tube headers, motor can't breath due to the small cam.

Valve events should always be figured out after all the supporting components are selected for intended usage.. As you said, the cam is the brains, if you don't go to school (supporting mods) how can you do your job (cam).

An optimal converter for best performance has to be selected once peak TQ RPM is identified. Otherwise you are only throwing darts.

This is completely wrong. You need to know what heads your using before picking the cam but the the camshaft and the heads together determine the power band. I have seen dyno where the victor jr made more power across the board over the dual plane when the dual plane should have come out the winner. I have never heard of doing it the way you describe in the 25yrs i've been playing with hot rods.