Hi,
I'm looking at rebuilding a 327 and could use some help on part selection, the car is as following:
CAR:
1965 Corvette (to far gone from original to go that restoration route)
M21 4 speed
4:11 12 bolt posi rear end
Weight 3200#
Engine:
327 l79
original block .030 over
heads double hump with 1.94 valves (not original or correct)
2.5 in ram horn exhaust manifolds
zz4 intake
eldebrock 600 cfm carb
Goals:
weekend driver, no racing intentions, I'm more interested in driving winding roads but would like some off the line performance.
325-350 hp
350 minimum torque (I do understand that this is a 327 and not a 383)
$ 2500 to $ 3000 budget (hopefully including machine work)
Intend to keep:
Block
crank
Rods (if feasible)
carb
intake
2.5 in ram horn manifolds
Intend to replace:
Cam
heads
pistons
and other required items for a rebuild
I am pretty set on keeping this block as long as it checks outs and would like recommendations for heads and cam replacement. I am willing to consider aluminum or cast iron heads, weight is not a real concern to me, also what kind of intake flow values should i be looking at for the heads? (I have looked though previous posts and have a basic understanding of high vs low flowing heads, so thinking on the lower end, just not quite sure what target should be.)
I plan on lowering the compression of the engine to be pump gas friendly (91 max octane in California). I'm assuming that this would be accomplished through different pistons. (present pistons are the 11:1 comp. l79 327 sbc). If my goals are unrealistic please let me know and your help is appreciated.
4.11 and 4 spd are the key features here. along with 11:1 cr pistons.
get some 180cc afr eliminator heads. these heads come in 65 and 75 cc. if you have 11:1 with a 64 cc head then 75cc will make 9:6:1 with the same setup.
with aluminum heads you can use 11:1 cr with 91 octane if the cam is big enough.
get a cam with 285 degrees on the intake and 295 on the exhaust with 110 to 112 lsa. You need more duration on the exhaust since you are not wanting to change to headers.
use a 0.040" felpro head gasket. this will lower the stock cr down a few points. 10.7:1cr with 0.040" head gasket and 11:1 with a 0.020" head gasket.
if you don't want to use a cam that big (285/295) then use the 75cc heads (9.6:1 cr) with a cam in the 270 degree range on the intake and 280 on the exhaust. still more on the exhaust since you don't have headers.
if you are going to change the pistons then it is better to use as flat top with a smaller chamber to get the compression you want. (better flame travel).
I would change to flat tops and stroke it with a 350 crank and use 64cc heads with headers and a compcan 292H. use a RPM intake with a holley 750. this engine will make 450hp at 7000 rpms and 400ftlbs. a cheap stock cast crank will work just fine. without headers 390hp, 375ftlbs. Yes, headers make a huge difference when big cams are involved. And make a lot more torque in the mid range even with a mild cam (+40 or 50 ftlbs).
4.11 and 4 spd are the key features here. along with 11:1 cr pistons.
get some 180cc afr eliminator heads. these heads come in 65 and 75 cc. if you have 11:1 with a 64 cc head then 75cc will make 9:6:1 with the same setup.
with aluminum heads you can use 11:1 cr with 91 octane if the cam is big enough.
get a cam with 285 degrees on the intake and 295 on the exhaust with 110 to 112 lsa. You need more duration on the exhaust since you are not wanting to change to headers.
use a 0.040" felpro head gasket. this will lower the stock cr down a few points. 10.7:1cr with 0.040" head gasket and 11:1 with a 0.020" head gasket.
if you don't want to use a cam that big (285/295) then use the 75cc heads (9.6:1 cr) with a cam in the 270 degree range on the intake and 280 on the exhaust. still more on the exhaust since you don't have headers.
if you are going to change the pistons then it is better to use as flat top with a smaller chamber to get the compression you want. (better flame travel).
I would change to flat tops and stroke it with a 350 crank and use 64cc heads with headers and a compcan 292H. use a RPM intake with a holley 750. this engine will make 450hp at 7000 rpms and 400ftlbs. a cheap stock cast crank will work just fine. without headers 390hp, 375ftlbs. Yes, headers make a huge difference when big cams are involved. And make a lot more torque in the mid range even with a mild cam (+40 or 50 ftlbs).
terrible quench, poor heads for the money, and too big of a cam duration split for a NA daily driver. 292H cam is more strip oriented than street. I agree with most of the rest.
TQ appears to be more of a concern than a high winding race engine...
terrible quench, poor heads for the money, and too big of a cam duration split for a NA daily driver. 292H cam is more strip oriented than street. I agree with most of the rest.
TQ appears to be more of a concern than a high winding race engine...
4.11 gear with a 4 spd already has "low speed torque" due to the engine revving so high. That combo needs an engine that makes power in the upper rpms (unless it is going into a tow truck).
what he really needs in a set of headers to make that mid rpm torque!!!
a 292H makes a nice "weekend" street cam. I have used that cam as just that and loved it. He isn't building a daily driver.
I have near that 350 setup with a 3.90 gear with a 5 spd in a 2800 pound car with 200cc darts. 1st gear is all torque and traction is very bad on street tires. Thankfully the engine pulls to 7200 rpm which gives 1st gear some pull at the end of the rpms when the tires stop spinning in the 6000 rpm range. With a smaller cam, 1st gear isn't usable, well maybe for a parking lot. Even with the 292H, I take off in 2nd gear most times.
the 292H is back to making torque at 3000 rpms which would be around 20mph in first gear (4.11 gear, 2.75 first gear, 26 inch tire).
I'm sure that works fine for you, but its not what the poster asked for. I see this a lot in my line of work. Engineers trying to design to their limits when a client just wants a simple and effective solution.
yes but i dont think the OP is looking for that aggressive of cam for what kind of drivig he plans on doing, and that is a larger duration cam for a 350 so it will be even that much more aggressive in 327
not saying that it's a bad cam a buddy of mine runs that in his street/strip C-10, i just think that's a bit much for what he is looking for
he can keep more compression with a bigger cam or drop compression with a smaller cam. Maybe the guy doesn't really want to change the pistons.???
also made a recommendation with a 350 build that he would love. Because, if he puts small cam in a light car with a 4.11 gear and manual trans, then it will drive like a tow truck. When someone wants to jump off a bridge I try to convince them otherwise.
a 350 with a big cam and 4.11 gears with a manual is not my invention. It works for everyone.
My information comes from my machinist, who's done all my work for over 25 years, does a TON of local racer's porting work, even has some national record holders, and owns his own Superflow 600, but I'm always interested in more knowledge and/or different perspectives...
Always listen to your machinist over some nobody on the internet. If you
don't, find another machinist. He is likely fixing some of the obstructions
in the vortec heads with his valve job. Besides its not cost effective to pay
much for porting vortec heads, if someone is going to get into them that
deep money wise, it’s best to start with a better casting IMO. Now if you
do the work your self, it’s a different situation. I’ll post some pictures of a
set I’m porting now.
You and I are on the same page with the RPMs. These small journal engines
handle RPM very well and anyone planning to spin one up should invest in
a good set of forged pistons. If you go back and study the combination I
posted, it’s really very mild with a power peak well below 7000 RPM, should
make over 400 HP.
According to DD2000 with AFR 195 Eliminator heads it would make "about" 441 FWHP @ 6500 and 412 FWTQ at 4500 and 5000 RPM so Peak TQ would be slightly higher somewhere about 4750. Yeah, it would be a lot of fun, definitely would leave no doubt to even non-car people that it was NOT stock.
My question is, where did the OP go? Still an interesting thread though even if he did bail on us.
Always listen to your machinist over some nobody on the internet..... He is likely fixing some of the obstructions in the vortec heads with his valve job...... I’ll post some pictures of a set I’m porting now.
He says most of his flow 238~242 after the valve job, also says he can get 10~15 more but it's not worth the trouble. So I think we're still on the same page. Apparently, you and I think nothing about taking a die grinder to a perfectly good set of heads, , but the average Joe can really mess them up badly without some teaching and/or experience, that was the reason I considered it bad advice,
here are some old vortec pics I have, I don't know if they're from the same set or different ones... I really need to label pictures better. It shows what a "average joe" can do with about a $100 investment in tools.
Not to pick on you, but while they look good, I would bet money those don't flow as much at .150 to .400 lift as a bone stock set out of the box, which is where the stock Vortecs with a GOOD valve job really shine. Got any flow numbers on them???
Not to pick on you, but while they look good, I would bet money those don't flow as much at .150 to .400 lift as a bone stock set out of the box, which is where the stock Vortecs with a GOOD valve job really shine. Got any flow numbers on them???
unfortunately, no. I have a few sets of heads I was going to take to my buddy's place all at once (he's two hours away), but with an upcoming wedding and house buying time is well... non-existant.
I'm curious though, what would you change? These were all taken before the valve job. The SSR is a hair flat at the top but I did my best to give it a good curve, they cc out right at 180. I would take some more of the current stuff i have but my camera was stolen when my truck was broken into. ain:
If you could give me some details I'm all ears. I've talked to a few head porters for tips and tricks but I'm just the average joe. I design landfills for a living.
4.11 gear with a 4 spd already has "low speed torque" due to the engine revving so high. That combo needs an engine that makes power in the upper rpms (unless it is going into a tow truck).
With a smaller cam, 1st gear isn't usable, well maybe for a parking lot. Even with the 292H, I take off in 2nd gear most times.
the 292H is back to making torque at 3000 rpms which would be around 20mph in first gear (4.11 gear, 2.75 first gear, 26 inch tire).
He has an M-21 close ratio Muncie with 2.20 first gear. Assuming a 26 inch tire he would be turning 6400 RPM @ 55 MPH in 1st, that better be one long parking lot!
I used to do a lot of porting, my 492s got the full treatment, the oval ports on my 427 flowed more than a set of stock square ports with MUCH better velocity and low end, did quite a few circle track heads for another shop here in town, but that was years ago, and they were a lot different animals than the Vortecs. Dennis, my machinist, would be the guy to ask, there are companies that make CNC plots from his port work for some of the import stuff. I just know he's told me several times that almost anything done to the port walls and bowls hurts flow, not help it. Chevy really did their homework on the Vortecs.
i didn`t change the bowl much at all though i did get into the runners some to straighten them out. i really need to get this stuff tested. got to get it by th misses to be though.
The pictures look good. I concentrate on three areas in the intake port, the
throat size, the push rod pinch and the width of the apex of the short turn.
Thats the only areas I remove much material.
I'm not concerned with low lift flow, the piston is still near TDC at that point.
The mid to high lift curve is more important IMO. If running a near stock
engine at low RPM low lift flow becomes more important.
On the exhaust side I resize and shape the entire port past the throat. I'll take
pictures when it warms up, no heat in the shop.
According to DD2000 with AFR 195 Eliminator heads it would make "about" 441 FWHP @ 6500 and 412 FWTQ at 4500 and 5000 RPM so Peak TQ would be slightly higher somewhere about 4750. Yeah, it would be a lot of fun, definitely would leave no doubt to even non-car people that it was NOT stock.
My question is, where did the OP go? Still an interesting thread though even if he did bail on us.
45 years old and with a fairly "mild" flat tappet cam, just think what a modern roller cam would do for it. That's why I think he should shelve the 327 and build a 350 with a factory roller cam block.
I have actual flow numbers for both sets of AFR heads saved in DD, I just wish there was more flexibilty on manifold and header inputs. BTW these numbers are with the "small tube headers with mufflers" file not open headers. EDIT: That's with a 650 and a dual plane manifold also, not the 750 and single plane.
Back "in the day" there was a guy here with a stock bodied '68 Chevelle SS with full factory interior running a single 4 bbl. 331 with a 4 speed and 5.13 gears that ran honest high 11's/low 12's on the strip. No big deal by today's standards but back then it was really something. This was the late 70's and nobody around here had heard of nitrous, it was all motor and except for open headers and slicks the car was street legal. He'd throw mufflers and street tires on it once in awhile and bring it into town. I don't know too many particulars on the engine but the cam was BIG and that thing would REV! Except for the Pro Stock like idle it would have passed for any other '68 Chevelle around, it even had a vinyl roof. Sunoco 260 was about $0.60 a Gal. and available everywhere, those were the days.....
Hi,
I'm looking at rebuilding a 327 and could use some help on part selection, the car is as following:
CAR:
1965 Corvette (to far gone from original to go that restoration route)
M21 4 speed
4:11 12 bolt posi rear end
Weight 3200#
Engine:
327 l79
original block .030 over
heads double hump with 1.94 valves (not original or correct)
2.5 in ram horn exhaust manifolds
zz4 intake
eldebrock 600 cfm carb
Goals:
weekend driver, no racing intentions, I'm more interested in driving winding roads but would like some off the line performance.
325-350 hp
350 minimum torque (I do understand that this is a 327 and not a 383)
$ 2500 to $ 3000 budget (hopefully including machine work)
Intend to keep:
Block
crank
Rods (if feasible)
carb
intake
2.5 in ram horn manifolds
Intend to replace:
Cam
heads
pistons
and other required items for a rebuild
I am pretty set on keeping this block as long as it checks outs and would like recommendations for heads and cam replacement. I am willing to consider aluminum or cast iron heads, weight is not a real concern to me, also what kind of intake flow values should i be looking at for the heads? (I have looked though previous posts and have a basic understanding of high vs low flowing heads, so thinking on the lower end, just not quite sure what target should be.)
I plan on lowering the compression of the engine to be pump gas friendly (91 max octane in California). I'm assuming that this would be accomplished through different pistons. (present pistons are the 11:1 comp. l79 327 sbc). If my goals are unrealistic please let me know and your help is appreciated.
ok, 3000.00 will probally be ok, but ca is high just because the state, u can search PAW out of chatsworth ca., they have good prices, are u doing this ur self or a shop, my shop could do this for approx 3200.00, and thats machine work, also their are nothing wrong with those heads, I would have them ported and polish, thats where ur money is going too go, so good luck, any more questions, just ask, or call, 317-401-0266 thanks scott
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