sb 400 - Impala Tech
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post #1 of 19 (permalink) Old 11-08-2009, 09:20 PM Thread Starter
 
 
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sb 400

hey guys i have a 65 impala with a sb 400 going in it but i want to add some additional hp to the engine. So far i bought some gm performance vortec heads for it. what would be a good intake,cam combo to go with this? i was thinking about the edelbrock performer rpm intake (#7116 vortec style) any advice would be great this is my first build so kinda new to it learning as i go along.
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post #2 of 19 (permalink) Old 11-08-2009, 09:27 PM
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For a street engine? Are you looking for high rpm or low end torque? Either way, good choice on the intake. Cam selection is always hard because there are tons of cams out there and tons of opinions. I would try a Comp 268 or 270 or Lunati's Voodoo line in similar grinds get good reviews as well.
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post #3 of 19 (permalink) Old 11-08-2009, 11:19 PM
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I have a mid rise bowtie intake on mine with a 650 edelbrock carb and a 110gph edelbrock racing fuel pump go with HEI also. If your rebuilding the block I would not go but 20 over on the pistons.

Make: Chevrolet
Model: Impala
Year: 1971
Doors: 4
Motor: 400 V8
Tranny: TH350
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post #4 of 19 (permalink) Old 11-08-2009, 11:44 PM Thread Starter
 
 
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well from what i heard the 400's have tons of torque so i guess higher rpm? not really sure what to go with but ive read that u have to match all this stuff up for it to run right i for got to mention i also have a holly 750 carb not sure if im going to stick with it. i was wondering if one of these cams would work

http://www.summitracing.com/parts/EDL-2103/

http://www.summitracing.com/parts/EDL-2201/

http://www.summitracing.com/parts/LU...1&autoview=sku

http://www.summitracing.com/parts/EDL-7102/
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post #5 of 19 (permalink) Old 11-09-2009, 06:00 AM
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Just remember that if your using the stock rods it will limit you in your upper rpms, as the stock rod is not conducive to reving. I have a stock rod motor and with a small crane econo power cam, full roller rockers and a vacuum secondary 750. That sucker will push you back in your seat and pull all the way from idle to 5K. My brother has a lunati 408 kit(both cars impalas) and that motor has a 6 inch rod and is noticeably more "peaky" when it comes to making power. The power doesn't seem to come on till much later but it will rev higher as well. The 5.7 rod is probably the best of both worlds. What ever way you build it.......400's are the shizzhoo!!!!!!!!!
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post #6 of 19 (permalink) Old 11-09-2009, 12:52 PM
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...and especially replace those stock rod bolts.

Of the cams you listed, I like the first one the best. The #2 and #4 are too big in my opinion, and that Lunati is too small IMO.

I like this range of cams....which are in line with what Matt66 said above. I copied this right off the Summit cams page for small-block chevy's.

I'm not sure what kind of compression ratio you'll have, or pistons..if non-stock,...or exhaust, but that would also play into just what cam I'd pick from that list.

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #7 of 19 (permalink) Old 11-09-2009, 08:27 PM Thread Starter
 
 
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wasnt considering the rods just because im not exactly sure what im doing or what all needs to be done lol, i figured the basic boltons would be enough but since i do have the engine out i might as well do what ever i can with in my budget and skill level. my budget from here on out is 1500 and i already have heads and carb and as long as its not to technical i feel i can do it. so thats why im here give me some suggestions this car will be street driven but i want it to GO so what ever u guys think will work with my heads let me know im here to figure this all out.
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post #8 of 19 (permalink) Old 11-09-2009, 09:26 PM
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Well get some Headers if your low go with shorty headers if stock height go with long tube and thermocoated.

Make: Chevrolet
Model: Impala
Year: 1971
Doors: 4
Motor: 400 V8
Tranny: TH350
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post #9 of 19 (permalink) Old 11-09-2009, 11:28 PM Thread Starter
 
 
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yea i plan on lowering it a bit so ill go with the shorty's
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post #10 of 19 (permalink) Old 11-10-2009, 09:54 AM
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Quote:
Originally Posted by nvrhapy View Post
hey guys i have a 65 impala with a sb 400 going in it but i want to add some additional hp to the engine. So far i bought some gm performance vortec heads for it. what would be a good intake,cam combo to go with this? i was thinking about the edelbrock performer rpm intake (#7116 vortec style) any advice would be great this is my first build so kinda new to it learning as i go along.
400'S ARE A UNIQUE ANIMAL........i think 69 or 70 they had 4blt mains?...but as far as heads go they had "steam holes?" cause the blocks didnt have full water passages if my memory is correct .....and the rotatin assm/crank...is externally balanced by the damper AND ring gear.....i would look into that with those vortec's .......since its your 1st build ...do lotsa research and ask q's before you go any further with your wallet!......
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post #11 of 19 (permalink) Old 11-10-2009, 10:48 AM
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charlie is right about those steam holes on the 400's. good advice to ensure the vortec's will provide what's needed for that. (they'll bolt on,...but, you probably need steam holes in the head to mate with the 400cid block)


charlie is on the ball!

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #12 of 19 (permalink) Old 11-10-2009, 07:00 PM Thread Starter
 
 
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i followed another build on a 400 and your right i do have to drill the steam holes in the heads so ill make sure that is taken care of for cooling purposes i also was going to try and get a 4 row radiator and run an electric fan for better cooling. My hardest part is figuring out what to go with in terms of rockers,rods(if necessary) cam, intake, and so on. i heard that u have to get everything to work together for the best performance. i have nvr put an engine together so not sure what to look for in terms of getting everything to work together.
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post #13 of 19 (permalink) Old 11-10-2009, 11:41 PM
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As for a 4 row rad that is not necessary a 3 row is a perfect rad for that motor I had a 4 row in my 71 and it was to cool now with the 3 row it is just perfect. I am running a 400 my build is!
Flat top forged pistons 20 over.
Steel crank.
Mild RV cam.
Over sized valves. can't remember the specs.
9 to 1 compression.
High output oil pump.
Balanced fly wheel a must for 400 sb.
Now for the bolt on's!
Mid rise bowtie intake.
Shorty headman thermo coated headers.
2.50 exhaust w/ 40 sires flowmasters.
650 Edelbrock carb.
110 gph Edelbrock fuel pump.
Summit racing H.E.I. dist. 50,000 volt.
Heavy duty clutch fan.
High rise valve covers.
3" tall 14" around air filter.
I am about 425 or 427 HP.

Make: Chevrolet
Model: Impala
Year: 1971
Doors: 4
Motor: 400 V8
Tranny: TH350
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post #14 of 19 (permalink) Old 11-11-2009, 05:18 PM
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RPM Vortec manifold and a mild hydraulic cam will keep you grinning ear to ear. The 400 is a torquey motor as it has a longer than stock small block stroke. To get the stock cast pistons to fit in the bores the factory shortened the rods. No stock rod bolt was all that great to begin with; but when you have the mass of a 4.125" piston on the small end high RPM's are not a good thing to be considering with stock rods.

It is your choice of cam that determines when your motor will make it's power. But it has to be able to feed the heads and the Vortec heads (which will out flow most aftermarket heads at lift values below 0.350" lift are going to run out of air unless these are bow-tie Vortec heads (service parts; not off a used pick-up truck). So I would be thinking around the 230° duration range at about 0.475" to 0.510" lift if you can find a stick in that range.

With a limited budget you will be happier with the stock parts refurbished and a set of headers and a mild cam. (those two items can rip old Grover Cleveland up, and chew a good ways through his friend William McKinley).

Big Dave
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post #15 of 19 (permalink) Old 11-11-2009, 09:11 PM
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quick addendum here, I just read this today and suspect it may play here.

I read that the standard Vortec heads cannot accept over a .480 lift cam. Something about some interference in the head/valve-train.
If that's true, I'm sure it can be machined/corrected but that just means more $$$ to someone else.

worth checking into when considering a cam choice.

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #16 of 19 (permalink) Old 11-11-2009, 09:32 PM
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Quote:
Originally Posted by BA. View Post
quick addendum here, I just read this today and suspect it may play here.

I read that the standard Vortec heads cannot accept over a .480 lift cam. Something about some interference in the head/valve-train.
If that's true, I'm sure it can be machined/corrected but that just means more $$$ to someone else.

worth checking into when considering a cam choice.
That is true of stock Vortec heads (they are limited to 0.480" lift due to coil bind and the valve retainer hitting the oil seal on the valve guide). Good news is the heads can be cut for larger valve springs (required of a larger cam) and the oil seal cut for the industry standard Perfect Circle nylon oil seal. Back on the bad news tally sheet the rockers are self guiding and have no guide plate under the rocker studs a $23 fix after you hog out the cast push rod guides in the heads (more machine work).

Big Dave

Last edited by Big Dave; 11-12-2009 at 08:55 PM.
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post #17 of 19 (permalink) Old 11-11-2009, 10:22 PM
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gimme a good cast-iron rebuild ....w/hot cam and a 600 holley anyday!

MR.CHARLIE
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post #18 of 19 (permalink) Old 11-11-2009, 11:45 PM Thread Starter
 
 
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so with the lift limitation that means i have to go with the first cam i listed correct?http://www.summitracing.com/parts/EDL-2103 in the description of this cam it says it has a smooth idle i kind of wanted something with a nice lope to it. seems as this post continues it gets more confussing to me with the lift/duration mixed with the heads i got https://store.gmperformanceparts.com...umber=12558060 and it does say no more than a 475 lift, i didnt know that
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post #19 of 19 (permalink) Old 11-12-2009, 10:37 AM
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if you want the loppy sound...and be very streetable...get the summit cam that is almost the equvilant of the COMP CAMS 268h....i have it in my 350....a couple of guys up north had it in their hillbilly hot rods (pick -up's)...it sounded real nice ...and very cost effective...from what i recall the only diff from a true COMP CAM 268 versus SUMMITS version was the center line degree's i think COMPS is 112#....an SUMMITS is 110#.....?...not positive on this but check it out.....and dave hit on somethin very important with regards to "air"....if you can't move it on both ends..intake as well as exhaust...your gonna have a "dirty" charge in your hole because with too much overlap you'll have incomin clean gettin mixed with outgoin exhaust.....and the engine will fall flat on its face.....so be cautious with your choice....with cams an small blocks it has been proven over and over again ...that too much cam will have you pullin hair outta your head...be conservative...and if you want to impress consider a gear-drive to go with a smaller cam....their noisey!....an people will be .."wtf!...ya got a blower under there?......

MR.CHARLIE
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