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Old 12-29-2012, 05:13 PM
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Big Block for towing

I'm building a '79 4x4 dually with a turbo 400 transmission and I'm putting a '89 454 in it, the truck is just gonna be used for towing a couple vehicles at a time, I'm wanting to get all the horsepower and torque out of this engine that is possible and still drive on the road with no problem, I plan on stroking it but I just don't no what size to go with so my questions are

which is best to stroke it to 496 or 511?
what are the best heads cam and intake I can get to give me the most towing power?
and finally what kind of horsepower and torque do you think the set up will make

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Old 12-29-2012, 08:43 PM
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more cubic inches is always better, pretty much no matter the intent

personally I would build the 489 or 496 since you can buy a 4.250" cast steel crank instead of having to fork out the money for a forged crank.

a decent "claimer" style rotating assy with a cast crank, forged rods and hyper pistons with do fine for what you are trying to accomplish. If what you are trying to do is towing then you want your power to kick in down low so that your tq band and peak is lower in the rpm range. For this you will probably end up needing to go with around 9.0-9.4:1 compression, since you shouldn't be turning a bunch of rpm you wont need a large runner head. I would say a head with a runner volume in the area of 270cc-295cc would do just fine. Then as far as an intake goes, my personal favorite is the performer rpm intake. then I would go with a carb like the Holley 770 vac sec on up to the holley 870 vac sec carb. As for a cam I would look at a hyd roller cam (flat tappets are next to obsolite now a days) with around 225-235 @ .050, a cam with this kind of duration in a 489-496 should start it's power band around 1400-1500rpm, it wont want to be reved up past around 5400rpm and it will make goobs of tq around 2500rpm.

I would estimate a set up like this in a 489-496 to make around 450-500hp but with around 600-625tq
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Old 12-29-2012, 09:03 PM
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I would use the oval port heads from GM.My 454 was a 360 HP LS-5,I put 2.19/1.88 valves,a used performer intake,before I took the car to the track I had a BB quadrajet and headers..For towing,if you want a roller cam,something like
120235-12 CL120235-12 266 274 213 221 .510 .538 112 108 Hyd. Hyd. 1,2
1400-4600 Good idle, Off-Road & Street Performance. 9.0:1 CR advised.
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Old 12-30-2012, 07:09 AM
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your gonna tow, so I'd think torque and service,
I'd build a 489 as it's only a 30 overbore.. the 496 is 60 over and with towing heat , you don't want the cyl walls thinner that you have to..
oval heads , depending on gearing.. dare I say a peanut port top end. with a hyd roller for low to mid range torque.. forget hp.. you'll mostlikely never see north of 3500rpm..
if building with p port heads scares you. I'd use g.m. oval port heads, and shoot for 8.8 to 1.
remember you'll be towing, and building tons of heat..
I'd even think of adding a water/meth injection for every punch over hills..
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Old 12-30-2012, 07:13 AM
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engine oil cooler

I found a factory engine oil cooler in the bone yard on a Uhaul type moving truck, I will replace the hoses when I install it. but it all looked to be in good shape. $ 20 so I had to have it.
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Old 12-30-2012, 07:51 AM
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Originally Posted by timothale View Post
I found a factory engine oil cooler in the bone yard on a Uhaul type moving truck, I will replace the hoses when I install it. but it all looked to be in good shape. $ 20 so I had to have it.
my 454ho instructons said if I used one I needed to change out the spring in the oil pump or filter adapter, can't remember which..
keep that in mind
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Old 12-30-2012, 03:46 PM
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I'm sorry but I just can't bring my self to advise the OP to use factory GM heads that were designed over 40yrs ago. There are so technologically outdated by todays standards it's not funny. Head technology has taken leaps and bounds over the past 20yrs. In my opinion pretty much any of the heads used in the 60's-70's are now obsolite. The only facotry head I would suggest to anyone now is the 906/062 vortecs, and even those should only be used when there is a serious budget issue.

The GM oval port heads had large runners but didn't have very good flow charactaristics. these issues acutally hinder making good hp/tq from begining to end of the power band. The whole idea of trying to buy heads is to buy the smallest runner heads that gives the best flow possible. typically if you can find a 290cc head that will flow nearly the same at .600" as a 325cc head then the 290cc head will make for a much broader power curve and make more usable tq since it creates more velocity at a lower lift and rpm.

take a look at these numbers:

all these gm oval port heads- 781,772,702,290, and even the 390's are all similar in there flow numbers. They range around 210-220cfm@ .300" and 255-275cfm@ .600". Now that is without any work being done to them, as they were cast.

yet you take a pair of aftermarket heads in the 270-300cc range and they are producing numbers in this area 220-235cfm@.300 and 325-350cfm@ .600"

they ones I would suggest are the Brodix 294's they flow out of the box 226cfm@ .300" and 337cfm@ .600". ****all of these flow numbers came from an independant site, not from the manufactures****

Then I can't bring my self to advise the OP to go with a cam that would be a "torquey" cam in a 396-427. The more cubic inches you have the more duration you need from the cam in order for it to react the same as a smaller cubic inch motor. A 210-215 @ .050 cam in a 396-427 will have a power band of around 1500-4500 but in a 489-496 it would have a power band of closer to 800-3800. Let me ask you guys this; if you wanted to build a mild "torquey" 383, would you use a 210-215 @ .050 cam that would be perfect for a mild "torquey" 327. No, you would use something with around 10-15 to achive the same kind of result (power band) since you have more cubic inchs. for you to have a power band in the 1500-4500 range, you will need to use a hyd roller cam with around 220-230 @ .050 in a 489-496.

I would estimate that if you used a set of GM oval port heads and a 210-215 cam that you will make around 380-400hp and 500-525tq. whereas if you use what I suggested you will be in the 475-500hp/ and 600-625tq range. simple as that, and it would still be very streetable.
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Old 12-30-2012, 05:10 PM
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I'm gonna have to take a page from F-Bird'88's playbook and recommend a low compression 454 with cheapo peanut port heads and a small blower. Makes more sense to me than juggling naturally-aspirated components.
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Old 12-30-2012, 07:07 PM
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Originally Posted by techinspector1 View Post
I'm gonna have to take a page from F-Bird'88's playbook and recommend a low compression 454 with cheapo peanut port heads and a small blower. Makes more sense to me than juggling naturally-aspirated components.
yup.. buy'n new heads will not help this engine, as it'll never see passed 3500 rpm towing
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Old 12-30-2012, 07:09 PM
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Originally Posted by my87Z View Post
I'm sorry but I just can't bring my self to advise the OP to use factory GM heads that were designed over 40yrs ago. There are so technologically outdated by todays standards it's not funny. Head technology has taken leaps and bounds over the past 20yrs. In my opinion pretty much any of the heads used in the 60's-70's are now obsolite. The only facotry head I would suggest to anyone now is the 906/062 vortecs, and even those should only be used when there is a serious budget issue.

The GM oval port heads had large runners but didn't have very good flow charactaristics. these issues acutally hinder making good hp/tq from begining to end of the power band. The whole idea of trying to buy heads is to buy the smallest runner heads that gives the best flow possible. typically if you can find a 290cc head that will flow nearly the same at .600" as a 325cc head then the 290cc head will make for a much broader power curve and make more usable tq since it creates more velocity at a lower lift and rpm.

take a look at these numbers:

all these gm oval port heads- 781,772,702,290, and even the 390's are all similar in there flow numbers. They range around 210-220cfm@ .300" and 255-275cfm@ .600". Now that is without any work being done to them, as they were cast.

yet you take a pair of aftermarket heads in the 270-300cc range and they are producing numbers in this area 220-235cfm@.300 and 325-350cfm@ .600"

they ones I would suggest are the Brodix 294's they flow out of the box 226cfm@ .300" and 337cfm@ .600". ****all of these flow numbers came from an independant site, not from the manufactures****

Then I can't bring my self to advise the OP to go with a cam that would be a "torquey" cam in a 396-427. The more cubic inches you have the more duration you need from the cam in order for it to react the same as a smaller cubic inch motor. A 210-215 @ .050 cam in a 396-427 will have a power band of around 1500-4500 but in a 489-496 it would have a power band of closer to 800-3800. Let me ask you guys this; if you wanted to build a mild "torquey" 383, would you use a 210-215 @ .050 cam that would be perfect for a mild "torquey" 327. No, you would use something with around 10-15 to achive the same kind of result (power band) since you have more cubic inchs. for you to have a power band in the 1500-4500 range, you will need to use a hyd roller cam with around 220-230 @ .050 in a 489-496.

I would estimate that if you used a set of GM oval port heads and a 210-215 cam that you will make around 380-400hp and 500-525tq. whereas if you use what I suggested you will be in the 475-500hp/ and 600-625tq range. simple as that, and it would still be very streetable.
did you miss the part about TOWING AND DUALLY..
he'll gain nothing at the rpm he'll use his engine at.. other than a thinner wallet and LESS low end torque
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Old 12-30-2012, 10:14 PM
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"did you miss the part about TOWING AND DUALLY..
he'll gain nothing at the rpm he'll use his engine at.. other than a thinner wallet and LESS low end torque
"


I've built a fair share of engine and I have a pretty decent understanding about the math involed in acutally building and engine and not just assembling one!

Are you seriously going to try and tell me that a pair of larger oval port heads that are flowing 210cfm@ .300" and 265cfm@ .600" are going to out perform a set of aftermarket heads that have the same to smaller runner volume but yet are flowing 230cfm@ .300" and 340cfm@ .600". All the while the aftermarket heads will produce much better velocity across all lift ranges, there for creating better charge going into the cylinder on every intake stroke. A set of decent aftermarket heads and 220-230 cam will produce more tq in a 489-496 from 1500-5000rpm all day long than one assembled with a set of 40+yr old gm castings with almost any cam that you put in there. An engine is an air pump, the more air you can cram in there the more power it will make. If a set of heads can produce far better flow and velocity at all lifts than another set of heads than the better flowing heads will produce more power at every rpm level, not just higher rpm. last time i checked, those valves open a full lift (from .000-.600" or what ever your max lift is) each and every time that cam makes a full rotation, it doesn't matter whether you are turning 600rpm or 6000rpm.

let me ask you as far as small blocks go, if you were trying to make as much tq as possible in the 2500-3500rpm range, do you think it would be better to use a set of 40+yr old double humps (that flow like crap, much like the factory oval ports compaired to todays standards) or a set of DART, EQ, RHS, Brodix, Canfield...180cc heasds which are going to produce better flow and better velocity from .100-.500"

I'm not telling this guy to go out and buy a set of 325-365cc intake runner heads here, I'm telling him to go with a modest 270-300cc intake runner head that has been designed in the past 10-15years.

Come on now, its basic math comprehension here.
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Old 12-30-2012, 11:32 PM
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I would not modify the engine at all. It is just fine for towing.
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Old 12-31-2012, 12:03 AM
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I bought a brand new GMC 1 ton dually in December 88.It was rated at 230 hp,it is injected.It drove well and would spin the rear wheels about 10 to 15 feet. I dont think it would tow 2 cars all that great,but it would do it. an upgrade is not a bad idea.
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Old 12-31-2012, 07:32 AM
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Quote:
Originally Posted by my87Z View Post
"did you miss the part about TOWING AND DUALLY..
he'll gain nothing at the rpm he'll use his engine at.. other than a thinner wallet and LESS low end torque "


I've built a fair share of engine and I have a pretty decent understanding about the math involed in acutally building and engine and not just assembling one!

Are you seriously going to try and tell me that a pair of larger oval port heads that are flowing 210cfm@ .300" and 265cfm@ .600" are going to out perform a set of aftermarket heads that have the same to smaller runner volume but yet are flowing 230cfm@ .300" and 340cfm@ .600". All the while the aftermarket heads will produce much better velocity across all lift ranges, there for creating better charge going into the cylinder on every intake stroke. A set of decent aftermarket heads and 220-230 cam will produce more tq in a 489-496 from 1500-5000rpm all day long than one assembled with a set of 40+yr old gm castings with almost any cam that you put in there. An engine is an air pump, the more air you can cram in there the more power it will make. If a set of heads can produce far better flow and velocity at all lifts than another set of heads than the better flowing heads will produce more power at every rpm level, not just higher rpm. last time i checked, those valves open a full lift (from .000-.600" or what ever your max lift is) each and every time that cam makes a full rotation, it doesn't matter whether you are turning 600rpm or 6000rpm.

let me ask you as far as small blocks go, if you were trying to make as much tq as possible in the 2500-3500rpm range, do you think it would be better to use a set of 40+yr old double humps (that flow like crap, much like the factory oval ports compaired to todays standards) or a set of DART, EQ, RHS, Brodix, Canfield...180cc heasds which are going to produce better flow and better velocity from .100-.500"

I'm not telling this guy to go out and buy a set of 325-365cc intake runner heads here, I'm telling him to go with a modest 270-300cc intake runner head that has been designed in the past 10-15years.

Come on now, its basic math comprehension here.

yup it's basic math.. the smaller ports heads will make more power where he'll be use'n the engine..
your head choice will loose power from idle to 3000 rpm..
you know the rpm he'll be in 95% of the time..
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Old 12-31-2012, 09:54 AM
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"yup it's basic math.. the smaller ports heads will make more power where he'll be use'n the engine..
your head choice will loose power from idle to 3000 rpm..
you know the rpm he'll be in 95% of the time.."




REALLY!!!

Considering that factory GM Oval port heads have runner volumes from 265cc-up, most are around 270cc-290cc I find your point invalid. Like I said before, it's not like I'm telling this guy to get a set of 325-365cc intake runner heads here. I'm suggesting that he look into a set of heads with runner volumes from 270-300cc. Which just so happens to be the exact same size range that you will find GM oval port heads. The big difference is the fact that the aftermarket heads have far flow characteristics, they create better velocity at all lift ranges and all RPM ranges.

putting a set of crappy flowing, small 265cc oval port heads on a 489-496 is about the same as putting a set of 434 non HO 305 heads on a 383. Sure will it run, yes, will it make tq, yes, would they be out performed by a pair of aftermarket 180-200cc intake runner heads at absolutely every RPM level, YES!!!

The set up that I have suggested here; Brodix 294's with a dual plane intake, moderate 750-850 vac sec carb, 220 cam, will run just fine with a factory stall, the power band will be about 1500-5000. I would estimate it's max tq would be made right at 3500rpm. I would hope that he is running atleast a 4.10 rear gear for a tow vehicle, with around 30" tires put him running 3000-3200rpm at highway speeds.

The GM casting heads with the cam someone suggested (213) will make around 380hp/525tq MAX!, (that is likely generous) it will make its max tq around 3000rpm, so there for it will be making about 525ftlb of tq at 3000. Where as the set up I have given him would make around 485hp/625tq, as i already said it would make its max tq around 3500rpm so there for at 3500rpm it would be making 625tq, I would say that it will be safe to say that from 2000-3000rpm my set up will make more tq than the set up you are recomending. You know, the RPM he'll be in 95% of the time!


Please if you can't give good advice, dont give any advice


A cam similar to this would work well:

Howards Cams Retrofit Hydraulic Roller Camshafts 123515-10 - SummitRacing.com

You have to keep in mind that the manufactures rpm range estimation is made for a 427-454BBC, if you are going to stroke it to 489-496 that is a fair bit more cid, therefor you will need a bit more duration to achive the same rpm band.
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