The best fitting headers I have found so far have been the 2" Hedmans that are in the car now, no dinging and oil filter drops out, I've used Hooker Comps w/2" tubes, fit okay, had to ding a couple tubes, brake dist block on drivers side frame and pass. side to clear one of the A arms and the collectors hung down too low on my car, also used 1.75" Dynomax coated headers, had to ding tube to clear brake distribution block on them also and its a slight pain to get oil filter in and out with a kick out oil pan. I like the carb/intake choice, but you'll need to ask the pros about a cam choice.

 

James, glad to hear you finally got the engine to the builder! If I remember correctly I think you said you had grabbed a stock Winters intake recently, is the RPM really any better? Good luck with the new build, Happy Holidays,
Nat

 

Hi Nat, I was looking for a factory intake but never got one. I have an Edelbrock C427X that I got with a set of heads I bought but the divider has been cut out of the plenum. I don't want to use that one. According to the engine builder, Edelbrock claims a 20 HP increase over the Winters intake with the RPM intake. I trust what he says. I have known this guy for about 27years. He has been building big block chevy engines for over 35 years. I used to deal with him in the late 70s and early 80s. He's not cheap but I know his work. In about 4 or 5 weeks I hope to be ready to drop the engine in. I'm ready to get back on the road.
James

 

Still looking for some advice. What do you all think?
Thanks, James

 

Hmmm.... Everyone must still be on holiday break. Usually you would have gotten several responses by now.

My .02. Check out the Comp XE274 or wait for Harold's new product line to come out in a couple of months. His replacement for the Ultradyne 280/288 hydro should be the one to look at.

Rod

 

I ran Summit for $ 86.50 they are 1 3/4" primary and 3"exhaust ,the best part is that they fit like a glove in my tall deck 427 motor .

I use tall frame mounts and got about 1/4" of clearence in the back of the crossmember .

The next set will be a Dynomax 1 3/4" (same as SUMMIT headers ,I do not want to take chances with clearence problems ) but with ceramic coating .

What I can see is that alot of rectangular port heads users got 2"-
2 1/4" primary headers with big motors like 496 -up ,also you will find here in TC that alot of racers are running ovals with 1 3/4" headers with excellents ,excellents results.

I am not running a big inch BBC so I will keep the 1 3/4" headers ,they are working for me so far. GOOD LUCK

I got an 850 DP with a RPM AIR GAP with a 1/2" , 4 hole spacer on top of a open 1/2" open crosing the line at 6500 with 28" and 4.56 ring pinion ,I am shifting this motor very low at 5500 a drive the car to the track and is very far from home

 

Looks like a neat little motor. Here's my .02.

I personally am not too wild about hypereutectic's in my toys. Yes I know they are better than regular cast, Gm uses them in the new LS-7 etc, but if you're going to beat on something that doesn't have whizbang computer controls to keep it from hurting itself with detonation, I think forged pistons are a cheap insurance policy. Just seen to many come apart.

A 427 in that much car is going to need some mid range power...I think the RPM Air gap would be perfect. An 850 or an HP950 would be a good combo. Dual planes like a little more CFM. Don't be afraid to stick a decent sized carb on it.

Cams? Man we could go all night. Roller or flat tappet? What's your preference? Regardless, I wouldn't use anything less than .620 or so lift....and then we can work on duration and LSA after you tell us a little more. How much RPM do you want out of it?

I hate so see a 427 that can't rev....the average hyd is going to hurt a little here.

JIM


JIM

 

MERRY CHRISTMAS!

Now, I dont want it to sound like " mine is best" or anything like that there, but I did look into it for a bit and came up with...

243/251@ .050, .580/.602 lift, 110 LSA 276/284 seat duration. Solid. Good for power thorugh 6800 rpms. Requires around 135/340 seat pressures. Havent hit float w 7K rev chip ( going back to 7400 rpm with better valvesprings installed now and this is why I don't run hyper slugs in this 427 - its a revver ). Cam prefers installed at +4 to + 6. 2500 rpm stall min.

( with the shallow gears, I'd tend to keep carb size small, 750-800 and header pipes at no more than 1.875" primary id unless you plan on alot of converter - 3500 + )

At 10:1 and 3.42s, I wouldn't go much bigger. Shaun ( BLT4FN ) runs the next size smaller "non-race" solid and has had great luck with it.

My cam is http://www.holley.com/products.asp?product=402A3LUN

Shaun's is http://www.holley.com/products.asp?product=402A2LUN

Now the pros can compare to those. Good luck!

 

Thanks for the replies so far. There is some good info there. I just called my Engine builder and changed to forged pistons. This engine will be for street use only. It will probably never see over 6000 rpm. The converter I have now is a 3500 stall but I'm going to use a 2200 or 2500 one. I plan to use 2" headers with a 2 1/2" exhaust system. I'm thinking about the Pypes exhaust system but haven't decided yet. I think I'll stick with the RPM intake and 850 carb. I still have to decide on a cam but it will be a hydraulic cam.
Thanks, James

 

James,if I were picking a cam for your combo I would go with one of the new Voodoo grinds like this one.http://holley.com/products.asp?product=60204.
As for the headers,the Dynomax 1 3/4" fit our A bodies very well with no dinging.
I think the RPM intake and the 850 carb. will work for you.
I know you are anxious to get it installed and running.

 

I had a 274 XE in my engine when it was a 454. It pulled hard to 6000+. The noise it made was on the loud side. They slam the valves shut at a high speed due to the ramps of the cam this came from a tech session Comp had at Chevelle-abration a while ago and others on this site can tell you about the noise. I wished I had used it in my 489. Comps tech line said not to and the guy I was woking with talked me into a 280H, which I don't like.

 

James, if you're not screaming this 427 past 7000 DEFINITELY use the 1.75" headers.

And yeah, my cam is too big for only 6000 rpm. While I like the 276 Voodoo recommendation, the VooDoo 268 seems to fit the bill quite nicely and will mate with your 2200-2500 stall better.

 

Build it close to the L72 427 specs and you will have a low 12 second car that will last forever. Make sure that you use heavier valve springs to keep out of valve float, the major reason for dropping valves. Our 4:10 geared 427 Chevelle has the best part of 200K miles on it and the pistons still slid out of the bores upon disassembly. I'd forego the few horsepower and keep the Chevy intake for the stock look. Sneaky fast is the way to go. I've always used Hedman Headers and they always fit like a glove.

 

I agree, the 427 .060 over i built used the Smaller of the two cams 427L88 mentioned, the 402A2LUN. I dont have the converter or gears in my mind to justify the larger cam so i went slightly more mild. I have a 2400 stall and 3.55 gears. I think you have lots of good advice here, now go follow it

Daniel

 

I dropped my 427 off at the engine builder Friday. I am still undecided about a few things. I haven't picked a cam, intake and carb or headers yet. I need some advice. What I have so far is: 4 bolt 427 bored .060, 840 rect port heads and 7/16 dimple rods. He is going to cc the heads next week. I want to keep the compression at about 10 to 1 so I can run pump gas. I plan to use Keith Black Hypereutectic pistons. I want to use a hydraulic cam and Crane gold roller rockers. He suggested I use the Edelbrock RPM intake and a Holley 850 double pump. The heads will have Manley 2.19 and 1.88 stainless valves. This engine is going in my 68 Beaumont with a turbo 400 and 3.42 posi rearend. What headers will work and fit best? What do you think about the intake and carb combination? What cam would you use?
Thanks, James

after the chevelle is together,are you going to get the gear bug and go for steeper gears?----or stay set with 3.42s?--just something to think about---


Im an old school solid cam guy myself---so my advice on the cam is worthless---Im running 12 to 1 comp ratio--and 4.88s---60 over 427--one thing I can say is hooker 2 inch would be my choice--they will fit,and are high quality!--
bob hetrick