1 7/8 inch headers

[lilbowtie]

I was just asking, you seemed to be complaining about the money your were going to spend and a built 4l80e is about double the cost of a 400 and of course the converters are more. You can gear your car to run whatever rpm you want w/or w/o overdrive. If the 4L80E is your choice ok.

 

[kornball426]

I was just asking, you seemed to be complaining about the money your were going to spend and a built 4l80e is about double the cost of a 400 and of course the converters are more. You can gear your car to run whatever rpm you want w/or w/o overdrive. If the 4L80E is your choice ok.

I didn't mean to seem like I was attacking you or anything... I thought you were making some argument against the 4L80 like it's a bad choice.

Other than cost (which I'm painfully aware of) I don't see many downsides. I considered 700R4/4L60e, 2004R, and TH400 with a gear vendors overdrive. The 700 and 200 completely built costs more than a 4L80, which from what I've seen and read the 4L80 with just a performance rebuild kit and shift kit will be tough enough to handle the power I'm expecting this engine makes. The TH400 with a Gear Vendors would be bulletproof, but also costs a small fortune, the overdrive unit is like $2800.

 

[kornball426]

the problem is the more aggressive of an engine you build, aggressive cam,rage runner head, single plane intake, etc the less an engine likes to lug around at low rpm. All those pieces are mean to horsepower aka high air flow seeing as hp is torque times rpm divided by 5252. You don’t tend to use those parts to make torque monsters that make power in the lower rpm range. Why? All about airflow dynamics. If you’re cruising at 15% throttle and 2k rpm your engine will use the same amount of air no matter how big or small your heads intake cam etc are. However the bigger the ports the slower the air speed becomes which is especially important with a Carb’d engine because you need air speed in order to keep the fuel suspended in the air and into the cylinder. Even with port injection you still want good velocity in order to have consistent air charge in the cylinder. This is part of why people run higher stall converters with built engines like this even if only on the street so it isn’t lugging the engine all the time. Lower rpm the better for cruising isn’t always accurate, a real bad example but I’ve got a 94 ranger with a 4.0 and that thing absolutely loves cruising at 2800-3000 rpm. Most diesels like around 2000 rpm because they effectively make torque at low rpm. Some engines idle at 8-900 others have to be at 14-1500 to over come the drawbacks of making higher rpm power. Where your idle cruise rpm will be is decided on your combination, not what you think you want.

Honestly I'd prefer a dual plane manifold (and a cam to suit) but I'm having trouble finding any dual plane manifolds that are for large port heads, most of them are matched to a Fel-Pro 1204 or 1205 at the largest and I'm pretty sure these heads are matched to a 1206 intake which is raised port and most intakes don't have enough meat on them to open them up that large and still seal.

As a side note I ordered a cheap circle track set of schoenfeld 1 3/4 headers a couple days ago... They're going to fit perfectly... I may have to take a file to the port openings and take a hair off them... But the template I made fits the openings on the header flange almost perfect.

 

[565bbchevy]

The TH400 with a Gear Vendors would be bulletproof, but also costs a small fortune, the overdrive unit is like $2800.

I considered a built overdrive trans for my Monte but for my power level I decided to eventually go with a GearVenders after I install a new TH400 plus you get the over/under drive instead of just an overdrive.
My buddy has this set up in a 69' Nova behind a 632 BBC and he drives over an hour on the freeway to come down here where I live to go to car shows, Dream Cruise etc. it makes something with lots of power much more street friendly.
Obviously overkill for your set up though.

 

[kornball426]

I considered a built overdrive trans for my Monte but for my power level I decided to eventually go with a GearVenders after I install a new TH400 plus you get the over/under drive instead of just an overdrive.
My buddy has this set up in a 69' Nova behind a 632 BBC and he drives over an hour on the freeway to come down here where I live to go to car shows, Dream Cruise etc. it makes something with lots of power much more street friendly.
Obviously overkill for your set up though.

Yeah, part of me really wants it... But I know for the most part you're right, it's total overkill. Not to mention I can't really wrap my head around how to use the gear splitting, or as you say under drive.

It seems to me from the description they have on their site, you have to have to shift the transmission manually with a ratchet shifter that has a electric circuit which disengages the overdrive on upshifts, then engage the overdrive via a button either on the floor like an old school high beam button, or a shifter mounted button like you'd see with a trans brake in order to use it to split gears.

I can't imagine how it can do it if the transmission is left to shift automatically on its own. Even if you manually engaged the overdrive unit between gears, how would the transmission understand what was going on? There must have to be a way to automatically disengage it between shifts, or it would be the opposite of gear splitting, it would be more like skipping a gear, going from 2nd over to 3rd over. But I can't fathom how it would do it without shifting the trans manually.

 

[kbonanny]

I have a '78 w/A/C and I"m running a set of Hooker Super Comp 1 7/8 tubed full length headers. I wrap mine so the finish means nothing to me as this car is purely for "F U N "....though w/ slicks and a 4.10;1 rear gear it's well into the 10's! I no longer drag so I'm running the A/C, a 3:73:1 gear and a tight 3400 RPM converter to make the car very suited to cruising around with the ability to run on the highway turning right around 3-3400 from 60-70 mph. With the looser & higher stall converter & 4:10.1 gear driving on the highway for any length of time truly sucked!

Now...the good about these headers......I run the headers into 3" stainless Pypes X pipe, with dump pipes into a pair of Flowmaster 40 series mufflers then into 3" stainless Pypes tailpipes. I literally can easily run the tach to 7200 + RPM with this set up without even opening the dump pipes! If I had known I could get this performance through the pipes I never would have gone with the x pipe with dumps!
I use copper header gaskets & allen headed bolts to attach the headers, without much in the way of difficulty getting to every bolt head to tighten them. Thanks to the copper gaskets, I've never had an exhaust leak after tightening the bolts 2x after initial install.....and this has been years, literally! I also have very little trouble changing the plugs....way better than most other small block headers I've ever dealt with through the years.

The bads is simple. One singular issue, but it has zero effect when driving but makes parking lot maneuvers a bit tougher..... these headers have 1 tube on each side that goes outside of the frame rails. This is how they got the equal tube volume as well as why these headers make working around them a lot easier than normal small block headers. The issue is you lose a lot of turn with the front wheels...not an issue when driving but turn the wheels too far while maneuvering at low speed and you'll have a tire into the tubes...left side when turning hard left, right side when turning hard right. If this isn't an issue on your end, these headers are the best! I've never had an exhaust that offered the same E.T. THROUGH THE PIPES VS open headers before in my life....I know for a fact these headers allowed me to get the incredible performance I get over 5500 RPM as well.......incredible performance! The speed at which my engine (full roller stroker (383), Brodix heads) twists up after 5500 with these headers compared to others isn't even remotely comparable! I also used to be able to feel my peak HP @ 6800...not anymore! I've far exceeded my red line a few times as this engine pulls so damn strong in the high RPM range that I can't begin to feel any peak that I was able to not only feel but HEAR with smaller tube headers, different flange etc etc.

I am "looking" to see if anyone ever offers a set of G body headers w/ 1 7/8" tubes that allow retention of factory AC box and don't go outside the frame....but that's it....looking. While interested in knowing what is available today is nice, It would take an awful lot for me to opt to change out these headers.

PS If you wrap your headers prior to putting them in the car (except the removable pipes on each side, of course) you can get very good, symmetrical installation of the header wrapping that is by no means as appealing as stainless but at the same time don't detract any from the underhood appearance...though this may just be my opinion.

Kirk Bonanny ASE cert MASTER tech, 30+ yrs exp [email protected]