[455Dave]

I was running through a similar thread today so I figured I would start a new topic so I didn't confuse anyone.

If anything goes right, I'll be tearing down the T/A for paint this fall. I figured it would be a good time to swap my 96 heads for a set of 87cc E heads. Here's the current setup:

76 T/A, 455, ST-10 4 speed, 3.42 gears
Stock rods and pistons with the pistons about .025 in the hole
Ultradyne 288/296
1.5 roller rockers
Performer RPM
800 cfm quadrajet
1 3/4 inch Hedman headers to a Flowmaster Force II exhaust (2 1/2 inch transverse muffler)
Modified and curved HEI

If I install the E heads, I'll need new headers but I'm not sure on the primary tube size. I want to use a Dr Gas X pipe and traditional mufflers to replace the Force II setup. Here's the questions:

1. Should I use 2 inch headers?

2. Is a 2 1/2 inch exhaust large enough?

3. Will 1.65 rockers help with the E heads?

Dave

[455Dave]

I was running through a similar thread today so I figured I would start a new topic so I didn't confuse anyone.

If anything goes right, I'll be tearing down the T/A for paint this fall. I figured it would be a good time to swap my 96 heads for a set of 87cc E heads. Here's the current setup:

76 T/A, 455, ST-10 4 speed, 3.42 gears
Stock rods and pistons with the pistons about .025 in the hole
Ultradyne 288/296
1.5 roller rockers
Performer RPM
800 cfm quadrajet
1 3/4 inch Hedman headers to a Flowmaster Force II exhaust (2 1/2 inch transverse muffler)
Modified and curved HEI

If I install the E heads, I'll need new headers but I'm not sure on the primary tube size. I want to use a Dr Gas X pipe and traditional mufflers to replace the Force II setup. Here's the questions:

1. Should I use 2 inch headers?

2. Is a 2 1/2 inch exhaust large enough?

3. Will 1.65 rockers help with the E heads?

Dave

[Brian Baker]

1. No
2. Yes, but a 3" may be better.
3. Yes

[455Dave]

So 1 3/4 inch headers will work with the E heads. My problem is trying to find a set of round port headers that fit as well as my D ports do. I wonder if I could order a set of round port flanges and weld the D port tubes up to them. Are the port positions on D ports close to the round port heads?

I need to check on the Dr. Gas pipe sizes, I'll do that tonight. For some reason I thought 3 inch was the smallest size the X pipe came in.

I kinda figured the 1.65 rockers would help with the heads. It should put me at .536 intake and .558 exhaust. If I use tall valve covers I'll have to modify the AC bracket on the back of the compressor.

Thanks Brian,

Dave



[This message has been edited by 455Dave (edited 08-29-2001).]

[Brian Baker]

Dave, no problem. I'd like to add however that (IMHO) you'll be undercamming those E-Heads. It'll still run better than your unported 96's, but not as well as if you took advantage of the head with more cam (something with at least 240 degrees duration on the intake and around .600" net lift at the valve).

2" headers won't benefit until you get above 600-HP, and to put that large of a header with a 288 cam will be like throwing a hot dog down a hallway. 3" headpipes with 2.5" tailpipes will work great in conjunction with the X-pipe. Spend the cash on a quality set of headers that fit (figure $500-600), cutting the flange off the d-port headers and rewelding them to a round port flange will be troublesome and a headache.

One other thing. I'd also consider going over the bottom end as well, at the very least installing new forged pistons, but preferably forged pistons and rods. Doing so will go along way longevity wise with the extra power coming on with the E-HEads.

[455Dave]

I know the cam is too small for the E heads, but if I can swing this deal, it will be worth it. I figure to put the E heads on the current 455 and look for another engine to build for the E heads. That will let me run them now [img]/infopop/emoticons/icon_smile.gif[/img] and give me time to put a proper short block together.

Dave

[Skip Fix]

Round port headers for sec gen F body I own.

2" Hooker Super Comps, good fit , BIG tubes.Same thoughts as above.

1 3/4 Hedmans My set had terrible fit, hity the firewall and poor flange. Cut off two tubes a side and they fit great now. Good size for a 400 probabaly a 455 with the cam you have.

1 7/8 Hedmans Good fit, good quality. Passenger collector was pointed at tranny but they changed that N/C.

The new ones Tom Hand is having made are a tri Y and look good. Knowing Tom they will fit great.

No sure if Doug's has any for the F bodies like his new ones for the A bodies.

I wouldn't go bigger than the 1 7/8" unelss you plan on some "spray" then the 2" would be better.

My current system for my roller cam E head 455 is the 2" Hookers 3 " headpipes and H pipe, 3" 2 chamber Flows(they are new to get replaced) and 2 1/2 mandrel bent Dynomax tail pipes. 400 was running 12 teens with teh 1 3/4 headers and this system, 455 first few outs 11.70s just motor. I didn't use the 1 7/8 as they don't have flanges to hook up to the street system now.

[larry davis]

Skip, I don't believe Hedman makes a set of round ports that will fit an F-body w/ 4-speed in any tube size? Please revert if you have first hand knowledge that they do. I am currently hung up on replacing my worked D-ports w/ Es, just can't seem to get all the exhaust **** together (but I'm close).

The Hooker Super-Comps are supposed to fit and clear all associated linkage(s) for 4-speeds. You'll be losing lower end torque w/ the 2" tubes and as stated previously, you'll need more cam to keep this combo from falling on it's face.

[455Dave]

Skip Fix,

Thanks for sharing your header experiences. My 1 3/4 inch D port Hedmans fit extremely well, I'll hate to see them go.

Is Tom Hand planning on producing headers for sale to the public? Aren't those the ones Rocky Rotella posted pictures of? I'd take a set of those in a heartbeat, if I could afford them.

BTW, I have a friend running the Super Comps on a 71 455 HO with a RAIV cam, 1.65 rockers. He runs mid to low 12s in a 4000lb bird that looks like it just rolled off the showroom floor.

Dave

[Skip Fix]

No experience with 4 speed fit. I'm pretty sure a friend has used the Hooker's with a 4 speed.A hacksaw, some mandrel bent tubes for any of the suppliers and a MIG can solve alot of fit problems, can even make then better than the maker!My Hedman 1 3/4 are really easy to install now and you can get to the bolts too! Gosh what a concept!

I think those are the headers Rocky mentioned from Tom.

[larry davis]

Skip, those 1 3/4" D-port Hedmans are THE best fitting & sealing headers I've ever used!

Just wish they made the same for the round ports w/ speed, I'd have a set of Es right now if so.

[Skip Fix]

I guess if you are really creative with a welder you could lop off the tubes at the flange and weld on some new ones. That's a little beyind me. I had to beg a friend to weld the two new tubes that I cut up on the round port ones.I need to go to a welding school.
If money is no object Dawson headers can copy the Hooker as he has that jig in what ever size you want. Probaly about $750. A friend has his round porrts on his 64 Tempest and they fit like a charm.