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post #1 of 15 (permalink) Old 11-21-2010, 03:14 PM Thread Starter
 
 
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327 build questions

so i have a 327 275hp engine, and im wanting to get it to around 325-350hp to the wheels and was wondering what all you guys recommend to get it there on a budget. engine runs strong but does smoke a bit, guessing the valve seats need replacing so im going to have the heads rebuilt and upgraded a bit.
so far here is what i have and plan on getting
i have a set of 1.6 aluminum roller rockers, electric water pump, hardened push rods, and hei distributor
i plan on getting an aluminum under drive pulley kit, electric fan, thumpr cam, intake mani and around a 600cfm carb as well as headers with full exhaust(not sure what you guys are running for headers on these cars as i cant seem to find anything performance wise that states that it will work), and a couple of other things like larger fuel pump, larger oil pan, high volume oil pump, etc any ideas on what a build like this might get to hp wise? or any ideas to get me to my desired 325-350 hp at the wheels?

also the car was a powerglide car orginally but now getting a saginaw 4 speed installed.

Last edited by Big Dave; 11-21-2010 at 04:40 PM. Reason: Post Script
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post #2 of 15 (permalink) Old 11-21-2010, 05:08 PM
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Quote:
Originally Posted by jcorkin View Post
so i have a 327 275hp engine, and im wanting to get it to around 325-350hp to the wheels and was wondering what all you guys recommend to get it there on a budget. engine runs strong but does smoke a bit, guessing the valve seats need replacing so im going to have the heads rebuilt and upgraded a bit.

so far here is what i have and plan on getting:
i have a set of 1.6 aluminum roller rockers, electric water pump, hardened push rods, and hei distributor
i plan on getting an aluminum under drive pulley kit, electric fan, thumpr cam, intake mani and around a 600cfm carb as well as headers with full exhaust(not sure what you guys are running for headers on these cars as i cant seem to find anything performance wise that states that it will work), and a couple of other things like larger fuel pump, larger oil pan, high volume oil pump, etc any ideas on what a build like this might get to hp wise? or any ideas to get me to my desired 325-350 hp at the wheels?

also the car was a powerglide car orginally but now getting a saginaw 4 speed installed.
Since You are on a budget forget about the electric water pump, and the electric fan. You do not need an aluminum under drive pulley kit, now or if you had an unlimited budget as the only thing you would be attempting to under drive in your plan is the alternator which would have to be spinning three times faster than normal to have any chance at making the amount of power you would need to keep the electric water pump, and the electric fan running.

A High Volume Oil Pump is used in a race car engine that has reduced the area of the rod bearings on the rods to obtain a greater fillet at the cheeks of the crank for increased strength (the radiused bearings leak more oil at a faster rate than regular bearings do). If you are reusing your stock cast iron crank you do not need a high volume pump. You will need a new oil pump just not a high volume pump (which is just a stock BBC oil pump stuck on a SBC anyway).

Finally if you are going to make your targeted horsepower a Saginaw transmission will not hold that level of power of 440 horsepower at the flywheel (take whatever horsepower you want at the wheels and multiply by 1.25 to get your flywheel horsepower; though with a standard trans you might get away with less as there is less parasitic loss with a manual than there is with an automatic). You are going to need a rebuilt Muncie transmission.

Which brings up this all important fact. Heads make horsepower. Not chrome or shinny aluminum, nor electric anything since you have to power whatever electric something off the crank anyway by way of your alternator (there is no free lunch). The most bang for the buck for a SBC head is World Products Sportsman II cast iron head. Buy that and you will not have to worry about rebuilding your old heads. As to a new manifold to put between the heads an Edelbrock RPM Air Gap manifold flows as well as a single plane manifold without loosing the benefits of a dual plane in making torque. Most young guns want a big thumping cam. The Thumper series from CompCams or the Lunati VooDoo cam both make their noise by extending the overlap on the exhaust side which doesn't hurt performance as much, to get the sound you want. Of course you won't make as much power as a shorter duration cam on the street but it gives you the all important noise everyone craves even though they have no idea how duration affects the engines performance (there is a reason race cars sound like they do and street driven cars do not).

Big Dave
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post #3 of 15 (permalink) Old 11-21-2010, 05:32 PM
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Gee, I am starting to sound like a broken record, but you can also get some more ponies by stroking your 327 to a 383. I am not sure how budget minded that is, but if you are looking at a rebuild, then things like the pistions are probably going to need replacing anyways.

A 383 with some modern heads like BigDave mentions should easily get you the power you seek while being mild mannered for the street.

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post #4 of 15 (permalink) Old 11-21-2010, 05:38 PM Thread Starter
 
 
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well i am getting the aluminum march pulley kit with new brackets for $200 and goes to a serpentine belt, i already have the electric water pump and i want to get the electric fan to clean up the engine bay a bit and get that big bulky fan out of the way, im going for a bit of show as with performance, i will probably be going with a 100-140 amp alternator as well since i will be doing a decent stereo system in the car as well as the electric water pump and fan. yes i am going with the cam for the noise it makes, i am fairly impressed with the way they sound with a decent exhaust on the car, i am going to look into the heads and intake you have recommended, however big dave do you have any ideas on a set of headers that will clear and what are the hp ratings for the saginaw and do you think a 600cfm carb will get a good match for the hp im looking for?
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post #5 of 15 (permalink) Old 11-21-2010, 05:41 PM Thread Starter
 
 
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as for now i am not planning on doing any bottom end work to the engine as it runs very well and feels very strong, so i am just looking at doing top end work and bolt on stuff for now but thanks for the insight.
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post #6 of 15 (permalink) Old 11-21-2010, 06:19 PM
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I'm not sure what the size of your budget is but I you wouldn't go wrong with either direction above.
1. stroke it for more torque, rebuild stock heads, keep rpms at something like 5500-5800 max because your old heads won't flow well above that.
2. keep it at 327cid and use aftermarket heads/intake/cam combo w/ power around 6500 - 7000rpm. (you'll need a 3.50-1 rear-end gear or better to make this worthwhile)
3. do it all!

I agree with Dave on the Dart Sportsman II heads on bang for the buck. I'm going to turn the tables here though because it's usually been Dave that recommends the Vortec, and me the Darts.
If you keep your cubic inches at 327 - you might be better served with the Vortecs because the intake runners are 185cc instead of the 200cc of the Darts. They are $140 cheaper for the pair at Jegs (assembled) but you give back $50 because the Edelbrock Vortec Performer RPM air gap manifold is more than the Edelbrock normal Performer RPM air gap. And you save 30-50lbs!
Like you said, a 600 or even 650 carb on a 327 would be good. If you stroke it, you could go 650-700, if you stroke it and get heads - go with a 750.

I've got no good tips on headers, other than to say I had multiple issues with my Pacesetters in the $200 price range) http://www.impalas.net/forums/showthread.php?t=2455

Bah - my slow typing and price referencing made my post a little late. Guess all the talk about the crank kit is for naught!

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Last edited by BA.; 11-21-2010 at 06:21 PM. Reason: because I'm slow
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post #7 of 15 (permalink) Old 11-21-2010, 06:39 PM
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Eh, go big or go home as they say. For the kind of power you are wanting, a low budget won't get you there. You can get close, but you still probably won't be happy with it, so you will end up spending more later on anyway.

I'd go with the 383 stroker, AFR aluminum heads, a nice cam with just enough sound, and an Air Gap intake. A Holley 670 Street Avenger carb would be a nice choice too.

Otherwise, I'd just leave it alone and do some minor things here and there.
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post #8 of 15 (permalink) Old 11-21-2010, 06:39 PM
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A set of 1964-'67 Chevelle headers will generally fit your 1965-'70 chassis if they do not list your model and engine application. Though almost everyone sells a set of headers for an Impala.

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post #9 of 15 (permalink) Old 11-21-2010, 08:31 PM Thread Starter
 
 
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so im thinking of going with a good set uofheads, thinking something with 2.02 and 1.60 valves with 200cc runners and a 64cc dome, that should keep the compression stock, as well as the thumpr cam, 1.6 jegs roller rockers, and a decent intake and carb, and full exhaust, should get me to around 300-325hp at the wheels pretty easily. i dont want to stroke the motor or anything, i want to keep the engine itself at the 327 size, this car isnt going to be a racer by any means when its done, i just want something that will sound good and be able to burn the tires up a bit every now and again without stressing the motor real hard, and even just for cruising afterall this is a boat of a car to get moving little extra power will be nice.
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post #10 of 15 (permalink) Old 11-21-2010, 08:43 PM
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You can fry the tires with a 307 for a little bit anyways. All you need are rediculously steep rear gears. With a set of 6.13 gears I could smoke the tires with a four cylinder before I ran out of gears in the tranny. The rear gear ratio multiplies the torque applied to the rear tires. Most old Chevys have a 2.56 or 2.73 rear gear set. Double that number and you double the torque of the motor effectivley doubling it's size (and halving the gas mileage in the process). This is why an increase in the number of your gear ratio is an increase you can feel in the seat of your pants when driving.

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post #11 of 15 (permalink) Old 11-21-2010, 08:48 PM Thread Starter
 
 
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but i dont want to gear it too low as i still want to use it for driving down the interstate at 70mph at a comfortable rpm range
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post #12 of 15 (permalink) Old 11-21-2010, 09:25 PM Thread Starter
 
 
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so i got to looking online and came across a pretty fair deal on a 454, might just keep my #s matching 327 and powerglide together and just put a 454 with 4 speed in the car any thoughts on this? if i go with the 454 the only thing i will probably do to the motor is just a thumper cam and exhaust. hopefully the saginaw can handle that power, the saginaw is off a fresh rebuild with hardened gears.
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post #13 of 15 (permalink) Old 11-22-2010, 10:25 AM
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The Saginaw three speed was installed behind a BBC, if requested (usually in a pick-up truck); however the Saginaw four speed was designed for the 110 horsepower Corvair engine. It held up as well to the four barrel fed 140 horse version of the Corvair Monza, but frequently broke behind the 160 horse turbo charged Corvair Spyder. It was adapted to be used in the Vega behind a four cylinder and the Monza even had it behind a 307 powered V-8 (Monza was a Vega with different sheet metal, and it offered a V-8 as an option). The Camaro used the Saginaw behind the 250 horse 327 but not the 300 horse version.

I can guarantee the Saginaw will not last long behind a BBC. I will warrant that the BBC will fry your tires upon demand at the push of the throttle pedal. Don't know how long the rear end will hold up to the abuse a BBC can dish out, but it will be fun right up until it breaks.

What you are looking for in terms of performance is torque. The 454 has that in spades compared to the 327. The 327 will have a higher peak horsepower number than the 454. Which illustrates the difference between torque (which is a measured commodity and horse power which is a calculation based upon torque and RPM (with the PM including the time function that the force is applied over).

Torque twists and breaks things but provides you with your acceleration. Horsepower allows you to overcomes friction and air drag so that a race car can whiz around the high oval bank at a NASCAR track. If you want maximum top end speed you want to maximize peak horsepower. If you want a really bad street car that can send your opponent home early you want the highest flattest torque curve you can get (which is synonymous with saying the most cubes you can stuff in a motor).

Bigger is better on the street, that is why there are so many 500+ cube motors out there sporting 402 decals. The other side of the coin is that a 454 decal on a 402 engine doesn't make it a 454 (I bought a lot of 396 engines that had 427 decals when I was younger before I learned to check the casting numbers before I bought the motor).

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post #14 of 15 (permalink) Old 12-03-2010, 10:56 PM
 
 
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Im looking into working up my 327 a bit too. Allready have the HEI ignition in it. Have a set of headers at home on my 79 Camaro anyone know if those would fit? Also got a Edelbrock Proformer intake and holly 600 or 650 carb sitting at home. Should those things give me a good boost? Once again I also am not looking for a race car just something with a bit of power that will be fun to drive.
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post #15 of 15 (permalink) Old 12-04-2010, 09:35 AM
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Quote:
Originally Posted by Brandonion1985 View Post
Im looking into working up my 327 a bit too. Allready have the HEI ignition in it. Have a set of headers at home on my 79 Camaro anyone know if those would fit? Also got a Edelbrock Proformer intake and holly 600 or 650 carb sitting at home. Should those things give me a good boost? Once again I also am not looking for a race car just something with a bit of power that will be fun to drive.
The Camaro headers should also fit your Impala as they were designed to fit in an engine compartment with much less room than found in the Impala. In fact most header companies make headers to fit a Camaro first and then list all of the vehicles that use the same steering geometry to apply the header to more applications for greater sales. To verify it will fit your car check the part number tag welded to your header and look up the application to verify it fits your car before you go to the bother of trying them on for size.

Once you have the headers installed then you will notice the inproved breathing offered by the bigger carb. The Edlebrock Performer intake is just a stock cast iron manifold that was cast in aluminum, it will not offer any performance gain other than reducing weight. Edelbrock makes five levels of performance with the Performer series being just like stock only made out of aluminum for better eye appeal.

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