The Stovebolt Site Forums The Shop Area Engine Shop rebuild 327 to 300hp????

I would like some advice on rebuilding an older 327 (late sixties) up to 300hp. Is it possible? And ok for everyday driver? Any rebuild kits anyone can reccomend?

sswapp

Wasn't the standard 327 4 barrel rated at 300 HP in 63 and 275 HP in 67? I'm not sure what that ment in reality.

mmm 327 as homer simpson might say 300 hp easy balance and blue print and read some of the new age small block preformance books.
got a 327 in my 57 jimmy dump truck a bit woreout now but will still run if i pull start it

63 Impala had two 327's, 250 hp & 300 hp. 300 had higher compression heads. Later that 300 hp became 350 with a 3 deuce setup. 300 hp is easy out of a 327, but you will have to shell out some bucks to go higher, say up to 400 hp.

300 h.p. out of a 327 ain't all that radical, more is easily possible. what heads you got? that's a biggie. gonna rework em i hope. blueprinting is a REAL good idea. gonna be in a truck? hood clearance for tunnel ram? hotter ignition? have seen 327's at over 400 h.p.--close to being too radical for the street---but still being cruised around town. if you want, i can hook you up with a buddy of mine at crane cams. he can work out the right cam, valvetrain, intake, and header combo to get you where you want to go. lots of things to consider--a biggie is --what trans you gonna run? different cams for lockup converters, etc. i don't know what experiance or knowledge you have, but remember the drivetrain is more than the engine, it's trans, differential gears, tire size--all has to be considered. next is what you want to do with it. i ain't trying to be complicated, just don't like to see folks spend alot of money and not be happy. have a good one

I read an easy way to guesstimate streetable HP potential from a V8. Multiply the displacement times 1.2, and that'll give a rough estimate of max streetable HP from a given engine. For example, if you multiply a 327 times 1.2, you get 360 HP. That means you can get about 360 HP out of a 327 and still get decent street manners. Try for more power than that, and the engine will idle poorly and require race fuel due to a hot cam and high compression. Thats when it becomes a race engine.

A general rule of thumb is that you're doing well to get one HP per cubic inch. 1.2 Hp/cu-in means you got the combo perfect.

Shoot for a compression ratio of 9.5:1, a cam with around 220 degrees duration and .475" lift, a dual-plane manifold, a 650 vacuum secondary carb, HEI ignition, mild porting of heads, block zero-decked. Bottom end balanced and blueprinted to factory clearances. Use TRW flattops and a good set of rods. Find a set of heads with 60 CC combustion chambers, large valves and screw-in studs.

These parts are just a suggestion, so do your own research to decide what RPM range you want. You should be able to get 300 HP with an RPM range of 1700-6000 or so.

You need to figure out what year 327 you have. The size of the crank journals changed in 67 or 68, so there is a "small journal" 327 with mains the same size as a 283 and a "large journal" 327 with mains the same size as a 350. I don't think the crank & rods from a "small" 327 will fit in a "large" 327 and vice-versa. This is where more research is needed for proper parts selection.

good luck & let us know!

chip

Man, you guys have it figured it out! Found out finally what I am going to try to do.

First: Get rid of my 1973 454 2 bolt, my 1968 307 two bolt, and my 283 2 bolt.

Second: Find a 327 4 bolt main to build up to the 1965 350hp stock engine.

Thanks for the info!!

whoa, whoa, not so fast there. You failed to mention you had a 454 biggie. You should build it stock and shoe horn it in there. Save the 327 for a roadster, 454 for yer truck.

And 4 bolt mains are so overrated. You don't need 4 bolts holding the crank in unless you're turning more than 6K RPM, or using a power adder like NO2 or a supercharger. IE, a full-out 500 HP fire-breathing, airplane-gas drinking race motor. The 4 bolt mains are to prevent cap walk and bearing distortion under extreme performance conditions.

A 2 bolt block is fine for street/strip duty. Use good quality ARP main bolts. Have the main saddles line-honed to true them up, and do the typical hot-rod stuff. You could get a 2 bolt 327, build it to 300 HP, and use bubblegum to hold the crank in and it would still run good.

chip

Good deal!! 4 bolts are a pain to find anyway. If anyone wants to make a trade for engine blocks, lemmee know- I'm be diggin' for a 327. Just a street machine, not a fire breathin' dragon. I'll go with the bubble gum crank. Thanks!

454 will hog up all my room for a/c and goodies. Also, with a camaro clip I will probably mash it into the street (have to upgrade all my suspension just to hold the weight). How would I deal with the [censored] end of my truck? The tires will get expensive having to replace em every 100 miles too. Small block seems to be the answer- unless there is something I don't get.....enlighten a beginner.......need all the help i can get.

Sell em all and get a 500 Caddy. Package isn't much bigger than the sbc.

I was being a bit silly with the bubblegum, but you get the idea. I've seen guys spend money and time to find a 4-bolt block, then fill it with parts that wouldn't blow a 2-bolt up.

Of course, the Small Block Chevrolet is the cheapest and easist engine to build and buy parts for. But the other side of the coin is that they get put in everything. SBC in a '50s truck. SBC in a Firebird. SBC in a Scout. SBC in a streached Harley frame. SBC in a blender. You get the idea. There has been some talk in the HiPo shop of using a 472-500 Cadzilla motors from late '60s, early 70s Big Caddies in other hotrod projects. Very trick, unique and those big motors made power.

Personally, I'd go with a Pontiac 400 or 455. They are bigger physically and cost more to build, but 425 to 600 HP is possible with a carb, pump gas, and decent idle. No laughing gas or 'charger needed.

Everybody's gonna have their .02 about what motor to use and how to set it up. Just decide what you want out of the truck.

chip

crazy crazy. Just want a nice, powerfull daily driver. Not a screamin' yellu fire breathing demon. I'll go with the 2 bolt 327- I don't have the patients to figure out all that big block stuff- I'm to young to have ever used a shoe horn- so I'll stick with the velcro shoes and drop a sbc in.

there is no substitute for cubic inches !! you have a big block why would you trade it for a small-block ??? you stated you had a camaro subframe the rat will bolt right in with factory big block motor mounts!! i have a 1968 camaro with a 454 and there is plenty of space besides a mild big block will give a built small block a run for its money !! use the oval port heads-keep compression under 9.5 to 1 a hydraulic cam and you can get 350-400 horepower and still have a engine that will idle good and also have the torque at 2500 rpm that a 327 has at 5000 plus pop the hood and big blocks look awesome !! just my 2-cents :rolleyes: :rolleyes: :rolleyes:

sswapp: I would have to agree with stretch 67, on this one. Will be a bolt in to your clip, with plenty of room for AC, etc.

You did not mention in your post what type vehicle
you are building, its weight, and your intended results.

You did state that you wanted a "powerful daily driver, not a screamer".

Are you building a "true" daily driver for around town and the highway, or might you sometimes be ready to do a little racing too?

You need to think about some basics:
1. reliability of the engine build-up?
2. what type transmission?
3. rear ratio?
4. manageable? (other drivers like wife, etc?
5. money you have to initally build with?
6. Will 300HP be enough?

Just some things to think about. FYI, the 327 never came in a 4 bolt version. Made from 62-68, with the 64 thru 66 375HP Ramjet FI version being the hottest factory offering. All 327's were 2 bolt blocks.

For pure fun, you just cannot go wrong with the BB. Parts are plentiful, but spendy. Can be built to more HP, than you have dollars to spend. I don't know about these other guy's and there BOP, or Caddie's, but I'll put my cash on the RAT every time. Properly re-built, provided your block is in good shape, the BB will give you all the motor you need. In my opinion, you just can't beat that slam you back in the seat feelin. Hitch that BB up to a Muncie M-21, and a 4:11 or 4:56 rear and you will be set. You new found problems will then become traction, and control.
Is'nt this build up stuff FUN!!!

Think Chevy!!! :rolleyes:

When I was still bracket racin' (early '90's), there was a guy with a full bodied '66 Chevelle 2dr HT that would pull the left front tire off the ground hard every time he launched off the line.

Yes, it was BBC powered. No, it was not a 454. It was a 396 with oval port heads, HEI and a good cam. 4.11's in the rear (posi of course!) and turbo 400 trans with a stall converter (don't remember what stall speed).

Sounded good with straight pipes........................man, I miss the track .

To stretch67 and Chevyman:

I also have a 68 Camaro, it has a 250, the car is in very good shape. I also have a 454, 4 bolta mains block, forged crank, R port heads, TRW 2399 forged domed pistons(.133"dome), Edelbrock Performer RPM cam(306'adv duration), holley 850, GM dual plane aluminum intake(LS6), HEI igntion. And I want to drop it into the camaro. Will use 4 spd, (clark 260, close ratio, available here, no mods required to fit in the car or behind the engine) sub frame connectors, hedmann headders for the above combo. It is all togheter yet, don't need to buy anything else, would You like to make any comments, any possible difficulties, anything worth saying about it?
The engine is brand new, I rebuild it for a 2 engines 31 feet boat, one was shot, this one was perfect, just got new bearings, rings and cam the engine is standard size all the way. This engine sounds pretty mean, and they went out of the boat just because of the fuel comsuption. Welding the subframe connectors instead of just bolting them sounds good to You?
Thanks in advance.

Chevyman,

As for the 261 boring topic some time ago, took a couple of blocks to the machine shop, got a couple of damaged ones, the ones cast here cannot be bored to much more than 3.810, no way to bore them out to 3,875. So I see no point in just trying to ofsset grind the crank, using the smaller 292 rods, first because of the rod width issue You talked about and second because it would allow a very small gain in displacement without the 1/8 overbore.
Thanks again, fellow!!

Best advice I ever got about the small block chevy was to make it breathe! Tighten up the lower end, balance and blueprint, and spend your money on the upper end. Big valves, the right cam, the right valve train, and get lots of air from the carburation to the tailpipe in a nice smooth flow... Just my .02

sswapp, I bought a 67 Chevell off the show room floor. It had a 325 HP 327, 4sp, posi rear. GREAT car! I don't remember all the particulars of just how the engine was set up. I do remember how sweet it was. The car handled well. It was hard to beat, even with me driving. The milage was good, if I could kept my foot out of it. That was hard to do. The logos on the front fenders read, 325HP 327 SS. It was a great set up, IMO. BB are great for making power. But they are also heavy and can make a car/truck a real hand full, sometimes it can be hard to use all the power.

The L-79 327- 325 HP engine in Chevelles was a good one .When the 327 came out in 1962 it was offered in a 250 and 300 hp versions in big cars, and Vettes. the 250 and the 300 hp have the same advertised compression ratio of 10.5. the 300 hp engine has a larger AFB carb and the double hump heads and larger dual pipes. The 250 hp had the single hump heads, Rochester or Carter 4bbl carb and a smaller diameter dual exhaust the same as a Power Pac 283. These versions were offered in 64-65 Chevelles and some say in the Chevy 2.Both used the same mild hydraulic cam as a 283. The factory 4 spd 300hp 327 had a standard dashboard mounted tach.Around 66 the 250 hp engine was dropped and the 300hp became a 275 hp engine. Advertised compression was 10.25 and a Q jet carb was used with single exhaust on some models.1964-65 Chevelles offered the hotter L-79 350-327 engine which was also used in the later smaller Chevy 2's.Vettes could be ordered with higher HP rated 327's with solid lifters as Chevyman says.My first V-8 Chevy was a 64 full sized cheap model Chevy, 4spd, 300 hp 327.Ran high 14's with a 3.70 posi. Was a fine engine in its day, very underrated but almost as good as the supposed terror GTO.A few friends had 327-350 65 Chevelles and 66 Chevy 2's, great engines.Of course my hind sight memory is always better LOL

There is no replacement for displacement

I am still waiting to see a Peterbilt or a Kenworth semi tractor with a 454 in it......... :p Remember the "horsepower" discussion? You ned torque to move mass, that's all there is to it. Horsepower is just a measurement of work done in a specific amount of time (acceleration).