Thread: 454 build - what intake and cam ?

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Hi all,

I bought a built up 454 mark iv engine to install into my 67 impala. I would like to install a different intake and cam before I put it in the car.

The intake is an Edelbrock Torker II which is Rated by Edelbrock for 2500-6500 RPM. I would like an intake that is designed to produce power and torque starting a bit lower than 2500 RPM.

i want to change the cam because I have heard this engine run and it idles too smooth. Yes i know, I should not chose a cam by what it sounds at at idle.... But I do want one that produces good power and torque as well as idles a bit rough.

Ok so heres the rest of the story.
Car is a 67 Impala sport sedan
Transmission is a Muncie M20
Rear end is 12 bolt, 4.10 and positraction
Tires will probably be 28" tall

289 block
781 heads
Compression ratio will be 9.5:1
It has roller rockers.
Headers with 2" primaries and 3.5 outlet
Carb is a Holley 750 double pumper

What intake and cam should I use ?

I was looking at the Edelbrock "performer RPM" intake

I was looking at the comp cams thumper or mutha thumper cams but am unsure of what is best for my application

Totally understand the want for the hot motor sound. While it may not be the most desirable street choice, it sure sounds good at the stop lights, lol!

The Thumper cams (and some others now have joined in) seem to do a good job of both worlds (sound and performance without losing too much low end). There will be scarifies though, so read up on all the specs and check their reviews, I would check out some of the youtube review posts to see which cam gives what you want.

Good luck!

And be sure to match the intake manifold to match the cam choice. The intake can not effectively lower the torque curve below the cam's curve. While a 67 Impala is a large car, a 454 with 4:10 gears and a 4 speed is probably not gonna lack at launch on the street anyway, lol.

make sure the intake will clear the hood----

Originally Posted by ceejay

What intake and cam should I use ?
I was looking at the Edelbrock "performer RPM" intake
I was looking at the comp cams thumper or mutha thumper cams but am unsure of what is best for my application.

You're solidly in the ballpark......

The Edelbrock Performer RPM (not the Air Gap model) will make more power on the street than any other manifold you could bolt on the motor. Use #7161 for satin finish, #71611 for polished (Special order non-returnable product, allow 4-6 weeks for delivery) or #71614 for Endurashine. Some fellows have reported drivability problems in cooler weather with the Air Gap model, so I'd play it safe with the standard RPM. All the preceeding numbers are for oval port heads. There is another intake manifold that I would use interchangeably with the Performer RPM, the Weiand #8018 Stealth, for use with rectangular port heads.

For a lumpy cam for a 9.5:1 454, I'd choose the Mutha Thumpr retro-fit roller cam, part #01-601-8. Big block Chevies are known for eating flat tappet camshafts, so bite the bullet and install a roller to begin with. Regular readers on this forum know that I wouldn't choose this kind of cam on a plate with fries, but if that's what you want, the 01-601-8 would be your best choice in my opinion.
01-601-8 - Hydraulic Roller Camshafts

Use all the air cleaner that you can fit under the hood, preferably 14 x 4 or taller. Use a drop base to get more clearance, like a stock steel piece from a BB Corvette or this ebay offering....
http://www.ebay.com/itm/STEEL-AIR-CL...-/361319982440
Here's a 14 x 5 if you could make it work.....
http://www.ebay.com/itm/14-x-5-Round...ZSS3cY&vxp=mtr
and a 14 x 6....
http://www.ebay.com/itm/AIR-CLEANER-...9UC3MC&vxp=mtr

Mo' filter area is mo' betta.....
http://image.hotrod.com/f/17907061+w...g_guide%2B.jpg

750 is the proper size for a hot small block, your big block will want more to make max power. Twice the cubic inches = carb CFM.

Read through this tutorial to learn the pitfalls of using a flat tappet cam in today's roller tappet world.....
http://www.crankshaftcoalition.com/w...ips_and_tricks

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Originally Posted by techinspector1

Regular readers on this forum know that I wouldn't choose this kind of cam on a plate with fries, but if that's what you want, the 01-601-8 would be your best choice in my opinion.
01-601-8 - Hydraulic Roller Camshafts

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Tech, I'm sooo proud of you!

Originally Posted by techinspector1

....Regular readers on this forum know that I wouldn't choose this kind of cam on a plate with fries, but if that's what you want, the 01-601-8 would be your best choice in my opinion.

Originally Posted by 36 sedan

Tech, I'm sooo proud of you!

I'd say Joan is already giving us a kinder, gentler TechInspecor1

Okay, in deference to Tech's new status, I'll say it:

Sheesh!!! Here we go again.

:facepalm: :: ::

Originally Posted by techinspector1

For a lumpy cam for a 9.5:1 454, I'd choose the Mutha Thumpr retro-fit roller cam, part #01-601-8. .

This is the sound I'm after https://www.youtube.com/watch?v=igyp...&nohtml5=False

would a Thumpr produce this or does this call for a Mutha Thumpr ?

If it's a Mutha Thumpr, I'm guessing you meant 11-601-8 ? the 01-601-8 is for a Mk VI and mine is a Mk IV big block

I live in Sri Lanka where the ambient temperature is 98 to 108 degrees Fahrenheit. (37 to 42 Centigrade)

Would I benefit from the air gap intake ?

One of the main points of changing a cam is to coordinate the static compression ratio with the intake closing point of the cam. Joanie just figured the closing points of a couple of cams and has determined that you would be better served with the Thumpr, part number 11-600-8. She says you will have plenty of low end power and should have plenty of thunder. She says "let the good times roll".

Intake closes 35.5 degrees after bottom dead center and should work well from 8.75:1 to 10.5:1 static compression ratio.

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Many thanks for your input with specific part numbers techinspector1 !! it is much appreciated !

I see Edelbrock says their performer RPM intake is for "Large oval port" heads.
Mine are 781. I have searched online and see the 781 heads called "oval port" what do they mean by "large oval port" ?

Had a look at the carb and it is a Holley list number 4777-2 which is a 650 CFM carb. While I do want very good low and mid RPM power and torque, I don't want to miss out on a lot of power by sticking to a smaller carb than needed.

Will I be ok with this 650 CFM carb or should I step up to something like a 750 ?

I think this would be a better choice Holley 4150 Carburetors 0-4779C - Free Shipping on Orders Over $99 at Summit Racing Commonly known as a "double pumper' and I would outfit it with an electric choke.

Originally Posted by ceejay

I see Edelbrock says their performer RPM intake is for "Large oval port" heads.
Mine are 781. I have searched online and see the 781 heads called "oval port" what do they mean by "large oval port" ?

The Chevy production iron heads 049 and 781 are the "large oval port" heads they're talking about, as opposed to some of the "peanut port" production iron heads.
http://www.grumpysperformance.com/heads2.jpg

You guys who have a set of peanut port heads in the garage may want to reconsider selling them for scrap though, read this link for more info on making them work for a very stout street driver....
http://garage.grumpysperformance.com...ck-combo.2900/

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Thank you !!

Ok so now I know what intake and what cam to use.

Last thing to decide is what carb to use.

I already have a Holley 650 CFM double pumper which has been used with this engine by the previous owner.

Should I stick with it or go for a 750 double pumper as suggested by NTFDAY above ?

The car will need to accelerate hard as opposed to drive at high speeds for long periods.

We have no highways. It will be driven in the city mainly and will need to accelerate hard to pull away from the modern Japanese cars which will no doubt try to out accelerate it :-)

Since you have the 650, I'd try it first. It'll be easy to go to more carburetor if you feel you need it later.

Depending on which transmission you have, first gear is either 2.52:1 or 2.56:1, so your first gear final drive with the 4.10:1 rear gear will be either 10.496:1 with the 2.56 first gear or 10.332:1 with the 2.52 first gear. Either of these will be solidly in the 10.0:1 to 11.0:1 range that I like to use for launching without running out of gear and having to shift at the other side of the intersection. Your combination should pull like Jack the Bear.

You will be making very good cylinder pressure and so you will want to keep an eye out for signs of detonation by examining the spark plugs regularly while using the best pump gas you can put in the tank. Your very next purchase should be a 10X lighted spark plug loupe like this offering from Longacre....
Longacre Spark Plug Viewer 50884
You'll need to be able to see way down on the insulator....either that or cut the plug apart.....

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When reading plugs, make a full power run through the gears, then go to neutral and immediately chop the igniton. Any idling or low speed use after the full power run will re-color the plugs and you won't be able to read what the motor is doing at full bore acceleration. Let me say this again, with emphasis.....Choose a place where you can make a full-power run, then go to neutral, chop the ignition, pull over, yank the plugs and inspect them right there.
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Find every bit of information you can that concerns tuning by looking at the spark plugs. I'll start you off with these....
Spark Plug Reading 101 by Mike Canter - Dragstuff
Spark plug reading
https://www.google.com/search?q=read...IQsAQIMw&dpr=1
https://www.ngksparkplugs.com/about-...d-a-spark-plug
https://www.google.com/search?q=read...urning+coolant
https://www.ngksparkplugs.com/about-...ut-spark-plugs
https://www.ngksparkplugs.com/about-...park-plug-faqs

When making changes, make only one change at a time and go over the results of that change. You may have to backtrack to your baseline before making another change.

Don't be afraid to experiment with ignition timing. There is horsepower to be found there. First, find the limit of advance that the motor will tolerate using the available fuel you have access to. With the BBC chambers, it will probably be around 38 degrees total, but you should experiment with this and keep detonation under control by reading the plugs. The first indicator of detonation will be little black specks up on the insulator that look like someone sprinkled black pepper on them. That would be little droplets of oil that have been smashed from the top ring land by the sledgehammer blows of detonation. Next thing you will see on the insulators if you don't do anything to correct it will be little silver specks. That will be your pistons coming apart.
Once you have found the max timing the motor will like, experiment with the timing curve and where you put the initial timing at the crank.
http://www.firstfives.org/faq/timing...ed_engines.PDF
Now, of course you will need to know where top dead center is to begin with, so here's how to do that.....
http://www.firstfives.org/faq/timing...ed_engines.PDF

You may find that you can completely eliminate the centrifugal advance function of the distributor and hook 'er up direct with full ~38 degrees of advance without any centrifugal advance at all.
http://www.nastyz28.com/forum/showthread.php?t=133740

If you get to a point where excessive timing at the crank makes the motor kick back against the starter, cut into the hot feed wire that goes to the coil and install a momentary on-off switch that you can control from the dash. You can use a push-button NC (normally closed) kill switch for this function, one that will tolerate the amount of juice that goes through the wire to the coil. A 15+ amp switch should do the trick. Recommend this Cole-Hersee 35 amp unit.....
https://www.waytekwire.com/item/4415...JhbhoCslXw_wcB

Operation would be as follows.....
Push the engine off switch and hold it in with your left hand.
Turn the ignition start key on with your right hand.
Once the crank if spinning good, let go of both switches and the motor will be idling. No muss, no fuss.
If you can find a good starter support, you may want to install that also if you can get it to fit around/between the header pipes.

If you like a nice, mellow exhaust note, install either an X or an H pipe between the two down-pipes immediately after the collectors. The H pipe is simpler.

I have never used wideband O2 sensors, but I have seen many of them on race cars through the years and am convinced that they are one of the best tuning aids you can have on the car. One in each collector would cut down on a lot of the guesswork and allow you to tune for max power.

Also, don't be afraid to use carb spacers for experimentation. Make friends with someone who works in a wood-working shop who can make you various thicknesses of spacers. Wood is the best material to use for this in my opinion, as it helps prevent heat migration from the manifold to the fuel in the carb bowl. Try both open spacers as well as 4-hole spacers, see which works best with your combination.

Also, experiment with installing an air shock on the RIGHT REAR ONLY. When a front-motor, rear-drive car accelerates, the left front and the right rear get light. Even though you have a posi rear, you may find that the car handles better with the proper amount of air in the air shock and more pressure on the right rear tire. See if you can find an old one that someone doesn't want anymore. I wouldn't spend a lot of money on this until I saw that I was getting good results from the way the car accelerated. Install a pressure gauge and keep track of how the car reacts with different pressures.

Begin considering adjustable upper control arms and polyurethane bushings in the rear. Mount a video camera under the car to see how the rear u-joint reacts under acceleration. You want to try to keep her straight under acceleration and the adjustable upper arms would allow you to do that. Under acceleration, the pinion will try to climb the ring gear in the differential, so that is what raises the pinion yoke and "bends" the u-joint. You may even consider a pinion snubber like the Chryslers used. Here's a good photo of your rear suspension....
http://img.photobucket.com/albums/v6.../2-9-08045.jpg
and here's a good photo of how a pinion snubber works, limiting housing rotation and keeping the u-joint square by snubbing the pinion up against a crossmember....
http://image.moparmusclemagazine.com...on_snubber.jpg

I can just about guarantee that if you show up at the burger joint with a video cam mounted under the car and tell anyone about it, there will be a run on video cam sales in the area. Heck, you could even do it with the video on your cell phone mounted under there. Also mount a very strong light so you can see what's going on.

And finally, begin removing weight from the car. Begin at the front with the bumper and bumper braces. Drill holes. Invest in some good-quality hole saws. Remove unnecesary parts. How about that 100 lbs of carpet and insulation? Do you really need a back seat? What about the front seat? Could you replace it with some lightweight fiberglas units? What about the heater? Do you really need a heater and all the weight of the associated coolant that runs through the core?
Is the battery mounted up front? NOOOOOO. Move it to the trunk directly over the right rear tire. Going racing with a full tank of gas? NOOOOOO, a quarter tank is plenty. Think outside the box.

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