[70-SS-502]

So some background, I've got an older zz502 from 2006 in a '70 SS. Its got Hooker Super Comps on it now that hang super low, about 3" of ground clearance with the newer UMI & QA1 front suspension that's been added. The rest of the exhaust has a few leaks & the Flowmasters on it are old, so I'm in the market for new headers that don't hang as low along with new exhaust all the way out the back. I'm not partial to any brand necessarily, currently looking at Hedmans #68198 which are 1.75" & Dougs D313 which are also 1.75". The shop that's performing the work has also suggested an x-pipe vs the h-pipe that's on it now.

My question is, since the headers are still on it, I don't know the exhaust port size & am wondering what size primaries I should order for new headers; 1.75", 1.7/8" or 2". Things are already tight in the engine bay, so I'm guessing 1.75" will leave the most room & give the best ground clearance, but will primary tubes of that size be the right size at the heads? Also, anyone with experience with either those Hedmans or Dougs please chime in with fitment issues, etc. Thanks.

 

[shovelrick]

I'm very happy with Patriot 1 7/8" coated headers, dynoed with them on my 489 590hp 600tq, which ever you choose get coated

 

[Lew540]

The 502 I think is a raised exhaust port engine so a smaller header will help with the fitment. No more than 1 7/8. If a 500 hp 502 the 1.75 would work fine especially with the raised port.

 

[70-SS-502]

I tried searching the other day to see if I could find out whether or not the exhaust ports are raised since some of these headers do not fit that style head & I couldn't find that info. Thanks for the help guys

 

[Malibu ss 64]

The exhaust ports are not raised on a zz502. Either one of the headers you are looking at should work. Dougs are better quality imo.

 

[70-SS-502]

I've been looking around at various forums regarding Hedmans fit & finish vs the Dougs & from what I've seen there's seems to be a consensus that Dougs are nicer but that the Hedmans tuck up higher & in this case I'm really looking for more ground clearance. They're both around the same price as well, around $700

 

[blm]

The Hedmans are nice fitting. Not familiar with the Doug’s so can’t comment. The Hedmans are pretty heavy gauge steel both flanges and tubes.

 

[NickeyChevelle]

Chevy recommends 2" primaries for the ZZ502's headers (ZZ502 Deluxe.pdf (crateenginedepot.com)). The ZZ502's exhaust ports are a squarish D shape (the flat part on the bottom) and measure 2" across and close to that up and down.

I had a pair of Hedman Street Headers (P/N: 68193) with 1 3/4-inch primaries on my ZZ454 (the ZZ454 uses the same head castings as the ZZ502's heads) and I had a problem with the upper corners of the exhaust gaskets leaking. I assume that a really good pair of exhaust gaskets may have solved the problem (the 68193 headers fit the engine compartment PERFECTLY and DIDN'T hand down). The 1 7/8 inch headers may also be a good fit in the engine compartment. On the other hand, the 2-inch primaries on my current headers REALLY WOKE my ZZ454 up (however they don't fit that great and they do hang down a lot), I imagine they would be terrific on a ZZ502 since the ZZ502 has the 2.25 inch intake valves and the 1.88 exhaust valves.

 

[70-SS-502]

Chevy recommends 2" primaries for the ZZ502's headers (ZZ502 Deluxe.pdf (crateenginedepot.com)). The ZZ502's exhaust ports are a squarish D shape (the flat part on the bottom) and measure 2" across and close to that up and down.

I had a pair of Hedman Street Headers (P/N: 68193) with 1 3/4-inch primaries on my ZZ454 (the ZZ454 uses the same head castings as the ZZ502's heads) and I had a problem with the upper corners of the exhaust gaskets leaking. I assume that a really good pair of exhaust gaskets may have solved the problem (the 68193 headers fit the engine compartment PERFECTLY and DIDN'T hand down). The 1 7/8 inch headers may also be a good fit in the engine compartment. On the other hand, the 2-inch primaries on my current headers REALLY WOKE my ZZ454 up (however they don't fit that great and they do hang down a lot), I imagine they would be terrific on a ZZ502 since the ZZ502 has the 2.25 inch intake valves and the 1.88 exhaust valves.

Thanks for the info. I'm really torn on whether to get 1.75" or 2" as I'd love the extra oomph form the 2" but the Hookers I have on there now I suspect are 2" & they leave me with 3" of ground clearance. At this point I'm leaning towards the Hedmans, either 1.75" or 1 7/8 as no one has complained about fit & most have said they're not as low as either the Dougs or any of the Hooker models.

 

[JodysTransmissions]

I have 2" primaries on my ZZ502/502 Gen VI. My 502 was when the Gen VI 1st came out in the 90s. I used the Hooker Super Comp Long Tubes. Fit was OK but, my friend has a ZZ502/502 and he bought a set of Lemons and I can see why they are expensive! The fit was unreal and they tuck up tight to the body for a lowered car. Lemon's will be my next purchase.

 

[blm]

I have 2 inch Lemons on my 496. Very nice headers. They fit wonderfully but are a very difficult installation.

 

[71454Chevelle]

I have 2 inch Lemons on my 496. Very nice headers. They fit wonderfully but are a very difficult installation.

Can you please elaborate a little about the difficulty of installation. What made it so hard to install? Any photos? Thanks.

 

[blm]

Can you please elaborate a little about the difficulty of installation. What made it so hard to install? Any photos? Thanks.

Very difficult to get them to the point that they can be bolted to the engine. They do fit and clear everything but getting them to that point is very difficult. After installing mine the ceramic coating is all scratched up. Also the passenger side header has to be unbolted from the head to install the starter. Or i should say the passenger side header must be put in place but left unbolted, then the starter (mini starter)must be installed and then header bolted to the head. One cannot remove a mini starter without unbolti the passenger side header.
I have installed and removed them twice. Both times I had a very difficult time installing them. Both times I was also installing the engine I had extra clearance. i doubt it would be possible to install them with the engine seated on the engine mounts.
I had another TC member contact me and ask me how I was able to install the 2 inch Lemons and the starter with the Lemons as when he tried it on his 67 he had extreme difficulty and scratched the coating on the Lemons to hell.
Different animal but for years had 1& 3/4 Hedmann Elites on my 396 and those were very easy to install.

 

[blm]

Also definately need to have front end of car raised. Might be helpful if the car was on a lift but still able to raise and lower engine.

 

[JodysTransmissions]

Also definately need to have front end of car raised. Might be helpful if the car was on a lift but still able to raise and lower engine.

Brad, did you use Dan's engine mounts and his mini starter? The '70 I installed Dan's headers has his mini-starter and can be replaced without loosening the header bolts. Dan warned me that the ZZ502/502 mini starter wouldn't work around his design.

 

[blm]

Brad, did you use Dan's engine mounts and his mini starter? The '70 I installed Dan's headers has his mini-starter and can be replaced without loosening the header bolts. Dan warned me that the ZZ502/502 mini starter wouldn't work around his design.

I used the Powermaster mini starter Dan recommended and purchased from him. But not his engine mounts.
There is absolutely no way the starter can be installed or removed without unbolting the header. Mine is a standard chevy big block with Brodix heads.
So Jody, how are you able to remove the starter? Out the bottom? Towards the front? I have a Milodon oil pan with the kickouts also. So out the bottom isn't happening however if I recall correctly after unbolting the header the starter is removed and reinstalled through the bottom.
One other tricky thing is running the positive battery cable to the starter. I had to bend the cable terminal to divert the cable away from the forward header tube. Also had to wrap the battery cable in header wrap to protect the battery cable from getting to hot. Prior to wrapping the battery cable the previous battery cable actually caught on fire. I was fortunate to catch it before it burnt my whole car up.