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I think Speedway has their own design and are not the same Trick Flow heads. (I may be wrong). BUT USE A Hydraulic ROLLER CAM!!!!
Do your research and you will find that flat tappet cams are failing at a high rate. I am doing a rebuild now after 1500 miles... Some say it's the cam, others the say lifters, and even the type of oil. Yes, it will be expensive! -- Not as expensive as doing it twice!
I am using Howards cams, great people to talk to and better customer service!
I am doing exactly what the same thing right now on my engine. I would do everything Joe posted. Since it is the numbers matching block, I would be very careful not to go down the rabbit hole of more hp, bigger cam, and stroking it.
You'll get more hp AND reliability than you will need with a very mild upgrade.
I would rather be driving mine not rebuilding it...
Trick flow sells the heads bare, for flat tappet or roller. Speeedway's are bare or assembled for flat tappet. Now, I went with speedway because I could not pass up the 499.00 each price. Now, I did have to drop the heads off at the cylinder shop to get new springs, retainers, keepers and shims.
I have read through this thread on April 12, after several responses have already been made. I strongly disagree with the view that it is okay to deck the block (removing the matching numbers on the pad). On the other hand, I agree with some of the other advice. Following are my thoughts:
1) Absolutely, positively, ensure that the block is not decked and the original matching numbers pad is preserved. Preserving the matching numbers block will have a big effect on the resale value of the car (about $10K difference). Even if you personally don't think preserving the pad is important, it may make a biig difference to a potential future owner.
2) The replacement frame and .030" overbore have zero effect on NCRS judging points.
3) Do not spend any money on the existing 3973487 heads or even numbers-matching original heads. Buy the Trick Flow DHC aluminum heads and paint them Chevy orange. Their external appearance will fool everyone except a very experienced NCRS judge, and their internal design greatly exceeds the performance of even ported stock heads. The cost is comparable to a set of fully reworked stock heads (stock heads with stainless valves, threaded studs, hardened valve seats, positive valve seals, pushrod guides, and pocket porting). Just buy the Trick Flow DHC heads and be done with it. Note that the 3973487 heads have mounting holes for accessories and are very obviously wrong for a '66. The '66 heads did not have these mounting holes in the front face of the heads. And the Trick Flow DHC heads don't have them either (if you purchase the correct version).
4) Do not re-use the stock rods. Buy a set of Scat Pro-stock or Eagle SIR budget performance rods. These are far superior to the stock rods, at a cost that is not much more than having the stock rods checked and re-conditioned.
5) For an inexpensive boost in torque and horsepower, do as DZAUTO has suggested and stroke the engine to 350 CID. All you need to do is have the mains journals turned down on a 350 crank. This is a very popular upgrade to a 327.
6) With the Trick Flow aluminum heads the engine will tolerate compression of 10.5 to 11.0 on 93 octane pump gas. With the 350 stroke of 3.48", flat-top pistons, and the 60 cc Trick Flow heads you should be in the right range with a suitable thickness head gasket.
7) From a performance perspective, the L79 cam flat tappet cam is perhaps the best all-around street cam that GM ever made for the small block. The only issue with using this cam is the possibility of wiped can lobes during break-in. A roller cam with similar duration and lobe separation angle (LSA) costs more but eliminates the risk of a wiped lobe. The roller cam can also have more lift while maintaining the duration and LSA of the L79 cam.
8) For highway driving at 70-80 mph, you will absolutely LOVE having a 5th gear overdrive of around 0.68. And, the 5-speed will come with a lower 1st gear ratio compared to a Muncie, which will give you a stronger launch from a standing start. If you don't mind the cost (about $4500), the Tremec TKX from Silver Sport Transmissions is an excellent choice. The 600 ft-lb torque rating of the TKX is overkill for a L79 clone, but otherwise it is a wonderful upgrade. For a typical small block, a Tremec T5 can be installed for much lower cost, as I have described in another thread on T5 5-speed conversions. Either way, the overdrive 5th gear makes a huge difference for driving at 70-80 mph. You will not be sorry for making the conversion to a 5-speed.
Damn I sorry I even mentioned the word "decked". Decked the halls... I am about to get decked by that comment.
And for you all "prestige worldwide!" There is a deck on there too.
Also, I have a set of 1.94s that I am not gonna use camel humps under the bench.
I would look into either Speedway or TF heads if you want to keep the look but want the modern stuff. I would still have a shop take a look at your application to make sure the heads will work with what you doing than just to bolt on the heads and run them out of the box.
Did anybody mention exhaust? The aluminum heads you fellas mention could be considered pretty much overkill without headers. As a matter of fact, headers would be the best bang for the buck performance modification you could make,
Did anybody mention exhaust? The aluminum heads you fellas mention could be considered pretty much overkill without headers. As a matter of fact, headers would be the best bang for the buck performance modification you could make,
The stock C2 exhaust system flows much better than the stock exhaust systems on most other cars. It is a true dual exhaust system with large 2.5" pipes, and the C2 cast iron ram's horn manifolds flow much better than most other cast iron manifolds such as the log-style Camaro manifolds. Headers still help, but not as much as with most other cars.
Since I had seen very little quantitative test data on the benefits of headers on a C2 Corvette, I decided to pay for an extra day of dyno time when I had my "L79 clone" 383 dyno tested (article attached). I had the dyno operator test four different exhaust combinations:
1) Open headers
2) Headers with stock C2 "offroad" mufflers
3) Open 2.5" cast iron ram's horn manifolds
4) 2.5" cast iron ram's horn manifolds with stock C2 "offroad" mufflers
The engine was similar to a stock L79 with the following differences:
* 383 CID instead of 327 CID
* Dart heads that flow about the same as the Trick Flow DHC heads
* Roller cam with L79 specs except for more lift
* Z28 intake manifold that is considered to be better than the L79 intake
Following is a graph of the measured results. While open headers made the most power (as expected), the difference between headers-with-mufflers and manifolds-with-mufflers was modest below 4000 rpm. For street driving, this is probably the most appropriate comparison.
If the OP sticks with 327 CID and the stock L79 intake, the horsepower difference between headers-with-mufflers and manifolds-with-mufflers will be smaller than they were on my 383. There is still a measurable benefit, but the benefit is small, especially below 4000 rpm.
Thoughts on this intake? It looks like the surface that mates with the carb has some sort of recess. It this a problem? First pic is of the intake I could purchase. The second is of an intake currently for sale on eBay. Any input of the first intake?
Thoughts on this intake? It looks like the surface that mates with the carb has some sort of recess. It this a problem? First pic is of the intake I could purchase. The second is of an intake currently for sale on eBay. Any input of the first intake?
The first intake has been modified for "performance". The added recess in the divider will impair the idle characteristic in exchange for a theoretical improvement in power at high rpm. Merging the two driver side holes is not helpful.
The second intake looks stock.
I'm surprised that you are thinking about replacing the intake that is on the car now. Are you doing this to create a "more original" appearance? Or is the existing intake a single-plane intake? I do think your intake should be a dual plane for better manners at low rpm.
If you just want a good dual plane intake that has an oil fill tube, the Edelbrock EPS 2703 would be a good choice. If you have your heart set on using an original '490 intake, send me a PM. I have one available.
I'm surprised that you are thinking about replacing the intake that is on the car now. Are you doing this to create a "more original" appearance? Or is the existing intake a single-plane intake? I do think your intake should be a dual plane for better manners at low rpm.
If you just want a good dual plane intake that has an oil fill tube, the Edelbrock EPS 2703 would be a good choice. If you have your heart set on using an original '490 intake, send me a PM. I have one available.
Sorry, I just realized that I had your thread confused with another thread where the engine currently has an aftermarket aluminum intake. If your engine has the 300 hp cast iron intake and you want L79 appearance, you definitely want an aluminum intake. Good original '490 intakes are expensive and their performance is mediocre. When considering the purchase of a used intake, keep in mind that many used intakes have had the corners break off and may not have been properly repaired. Study the photos carefully.
The best bang-for-the-buck is probably the Edelbrock EPS 2703 with the oil fill tube. Expect to pay $500+ for a nice original '490 intake. Most observers will not notice the difference between the '490 and the Edelbrock EPS 2703.
Adrian: I'm a fellow Utahan (Mapleton in Utah Co.). I also have a 66 vert that Ive spent the last year restoring. I replaced the original 300 HP 327 with a 383 stroker. Unreal how much more power and fun it is to drive. The original motor is refreshed (inside and outside) and is on an engine stand waiting for it's day. My philosophy is I enjoy spirited driving don't want to ruin the original motor. I'd recommend a stroker crate motor and keep your original motor for future use or for when you sell the car... Original # matching 327 383 stroker, about 150 more HP
The 327 (.040) in my car is running the EPS 2703. Performance wise I haven’t compared this intake to a different manifold.
The 2703 looks good and has nice flowing runners.
Carb pad height on the 2703 is slightly taller than the factory 490.
John
One small thing to note is that the chrome oil tube that comes with the EPS 2703 lacks the PCV port in the side. So, instead of using that oil fill tube, you need to buy a reproduction 1966 oil fill tube from one of the reproduction parts suppliers such as Corvette Central or Zip Corvette. For most of the used '490 intakes, you would need this part anyway.
Adrian: I'm a fellow Utahan (Mapleton in Utah Co.). I also have a 66 vert that Ive spent the last year restoring. I replaced the original 300 HP 327 with a 383 stroker. Unreal how much more power and fun it is to drive. The original motor is refreshed (inside and outside) and is on an engine stand waiting for it's day. My philosophy is I enjoy spirited driving don't want to ruin the original motor. I'd recommend a stroker crate motor and keep your original motor for future use or for when you sell the car... Original # matching 327 383 stroker, about 150 more HP
Not to hijack the thread, but what color is your 66?
Ray
Hey Mike, thanks!.. I have documented everything so I have lots of photos. I now have 2 nice C2's. Only 2 to go to catch up to you (-: BTW, I saw a recent post of yours about using the Por-15 Manifold Gray, so I ordered some and I'm redoing the exhaust manifolds on my original roadster motor. Thanks for the inspiration! I'm also enjoying the Tremec I bought from you in my coupe!!! Hope your hip surgery is healing up well...
One small thing to note is that the chrome oil tube that comes with the EPS 2703 lacks the PCV port in the side. So, instead of using that oil fill tube, you need to buy a reproduction 1966 oil fill tube from one of the reproduction parts suppliers such as Corvette Central or Zip Corvette. For most of the used '490 intakes, you would need this part anyway.
So true Joe. The Edelbrock oil fill tube that comes with the 2703 manifold is a bit chintzy in quality. A factory style reproduction oil tube was purchased from one the suppliers….I think it was Paragon.
The chrome replacement repro oil fill tube is of good quality. It also has the nipple that the PCV hose connects to on my ‘64 PCV system. The factory style oil fill tube fits tight in the mounting hole and allowed the PCV system to remain closed and intact also using the solid style factory cap.
I’ve read that the oil fill tube that comes with the
2703 fits somewhat loose in the manifold mounting hole. It was also mentioned that the supplied oil fill breather cap held in place with clips tends to vibrate and fall off the tube.
The factory style oil fill tube is the way to go, IMO. About 20 bucks at the time.
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
