Header size

[Darren 72]

I think this is a simple question for someone. I checked my heads which are 4V's but I think the Hooker headers are too small. I have a 351C engine. What size is needed for this set-up?

Thanks

 

[Tnfastbk]

351 Cleveland

1970-73 2V (Open) 74-77 cc intake port 2.02 x 1.65" Exhaust port 1.84 x 1.38"

1970-71 4V (Closed) 62.8cc intake port 2.50 x 1.75" Exhaust port 2.00 x 1.74"

CJ & HO 4V (Open) 74-77 cc intake port 2.50 x 1.75" exhaust port2.00 x 1.74"

 

[Widowmaker00]

I think this is a simple question for someone. I checked my heads which are 4V's but I think the Hooker headers are too small. I have a 351C engine. What size is needed for this set-up?

Thanks

What is done to the engine? The Hooker Competition headers you are most likely referring to are more than enough for a street engine.

 

[Darren 72]

I think this is a simple question for someone. I checked my heads which are 4V's but I think the Hooker headers are too small. I have a 351C engine. What size is needed for this set-up?

Thanks

What is done to the engine? The Hooker Competition headers you are most likely referring to are more than enough for a street engine.

I was talking to a guy that looked under the hood and said my headers were for a 2V not a 4V. Thats all I know. Not sure if it's true or not. Do they sell headers for 2V vs 4V set-ups?

I think this is a simple question for someone. I checked my heads which are 4V's but I think the Hooker headers are too small. I have a 351C engine. What size is needed for this set-up?

Thanks

What is done to the engine? The Hooker Competition headers you are most likely referring to are more than enough for a street engine.

I was talking to a guy that looked under the hood and said my headers were for a 2V not a 4V. Thats all I know. Not sure if it's true or not. Do they sell headers for 2V vs 4V set-ups?

I bought the car in June and am just starting to get into it.

 

[Tnfastbk]

they do make headers for both the 2v and the 4v. The main diff is the size of the header inlet or head exhaust port. 2v vs a 4v kinda like a golf ball compared to a tennis ball. The 4v is noticeably bigger. Check out a web site such as summit racing and look ur headers for a 351c. It will list both.

 

[droptop73]

The 2v headers will bolt up to 4v heads, not sure if they will seal though. 4v headers will not seal the ports on a 2v head, there are areas of exposed tube beyond the head casting.

 

[jorgem2]

Hooker makes 2 classes of headers for the 4V, the regular "competition" header which has 1 3/4" pipes and are marketed more for street use and the "Super Competition" which have larger 1 7/8 to 2" pipes more for racing. As well as a different one for the 2V port

He probably meant that the pipes are of the smaller variety and the same as the 2V headers he has seen before, which are 1 3/4"

 

[Darren 72]

Hooker makes 2 classes of headers for the 4V, the regular "competition" header which has 1 3/4" pipes and are marketed more for street use and the "Super Competition" which have larger 1 7/8 to 2" pipes more for racing. As well as a different one for the 2V port

He probably meant that the pipes are of the smaller variety and the same as the 2V headers he has seen before, which are 1 3/4"

Thanks for the help guys... I guess I should measure them and figure out what it actually is. Do the long headers at the correct size for a 4V head have issues clearing the steering box, too low etc...any issues here. Can I just bolt up and go with larger headers or will there be issues?

Another clue maybe....the car's Vin states H code. I'm wondering if the headers were on the original 2V heads. The heads are 4V's now. Maybe he didn't change out the exhaust when he upgraded? Would the smaller header restrict exhaust flow and allow some of the exhaust not to be discharged and the cylinders have a small percentage of the exhaust still in them during the next stroke cycle or intake cycle (which would steel horsepower)?

What are the best economical header for my set-up out there these days. I don't want crap but I also don't want to invest all my cash this winter in headers. I have other issues on the car that need attention.

Thanks for your help.

 

[Widowmaker00]

The difference between the 2v and 4v headers from what I gather from Jegs is the tube length, which varies depending on which style of headers you get, comp or super comp. The 2v headers are only available in 1 3/4 diameters, but 4v offer 1 3/4, 1 7/8, and 2".

Either 2v or 4v headers should bolt up fine to 4v heads. So in other words, they are the same headers, except some are longer or shorter. If you do have 2v headers it wouldnt really make a difference, being as header length doesnt really come into play until your doing some high rpm action.

1 3/4 headers are fine street headers for 4v and 2v, IMO you are good.

 

[Darren 72]

The difference between the 2v and 4v headers from what I gather from Jegs is the tube length, which varies depending on which style of headers you get, comp or super comp. The 2v headers are only available in 1 3/4 diameters, but 4v offer 1 3/4, 1 7/8, and 2".

Either 2v or 4v headers should bolt up fine to 4v heads. So in other words, they are the same headers, except some are longer or shorter. If you do have 2v headers it wouldnt really make a difference, being as header length doesnt really come into play until your doing some high rpm action.

1 3/4 headers are fine street headers for 4v and 2v, IMO you are good.

Thanks..I got some bogus info it appears. The guy that looked at them said they were the wrong headers..strictly for 2V but what you stated makes sense that they were used for both 2V and 4V. I need to measure them but I think they are 1 3/4"

 

[Hemikiller]

Hooker makes two series of headers, the Competition and Super Competition. The SC is intended for race cars and max performance street efforts. They have as-close-to-equal length tubes as possible. The Comp series is a "street" header and is a compromise of performance and fit. The performance loss would not be noticeable on the typical street car, but the ease of installation sure will.

Hedman also makes headers for this application, but you'll typically find Hookers on 71-73 351C cars, as they've been making them for a very long time, and were the only one that would work with a 71-73 standard trans up until about 5 years ago.

IMHO, the best fitting header is the Hooker Comp 6915 for the 4V heads. My guess is the 6921 2V is very similar and I'm sure it would fit just as well, but I personally have not used it.

The 4V headers will NOT seal on a standard 351C-2V head. The port of the 4V header would overhand past the gasket surface of the 2V exhaust port. They 4V headers will seal on an Aussie Cleveland head though, due to the wider exhaust flange area.

Hooker Comp:

2V Heads: 6921HKR (1 3/4" X 27" primary)

4V Heads: 6915HKR (1 3/4" X 27" primary)

Super Comp:

4V Heads : 6211HKR (2" X 34")

4V Heads : 6210HKR (1 7/8" X 36")

 

[Widowmaker00]

Hooker makes two series of headers, the Competition and Super Competition. The SC is intended for race cars and max performance street efforts. They have as-close-to-equal length tubes as possible. The Comp series is a "street" header and is a compromise of performance and fit. The performance loss would not be noticeable on the typical street car, but the ease of installation sure will.

Hedman also makes headers for this application, but you'll typically find Hookers on 71-73 351C cars, as they've been making them for a very long time, and were the only one that would work with a 71-73 standard trans up until about 5 years ago.

IMHO, the best fitting header is the Hooker Comp 6915 for the 4V heads. My guess is the 6921 2V is very similar and I'm sure it would fit just as well, but I personally have not used it.

The 4V headers will NOT seal on a standard 351C-2V head. The port of the 4V header would overhand past the gasket surface of the 2V exhaust port. They 4V headers will seal on an Aussie Cleveland head though, due to the wider exhaust flange area.

Hooker Comp:

2V Heads: 6921HKR (1 3/4" X 27" primary)

4V Heads: 6915HKR (1 3/4" X 27" primary)

Super Comp:

4V Heads : 6211HKR (2" X 34")

well said. Thats strange, the hooker site has only the heads you listed, but Jegs has 2 different 1 7/8th super comps available.

 

[Hemikiller]

I just looked at Summit and they show the 6210 and a 6211. i updated my post to reflect that. The 6210 must be new, I have a set of the 6211 2" primary headers.

 

[Widowmaker00]

I just looked at Summit and they show the 6210 and a 6211. i updated my post to reflect that. The 6210 must be new, I have a set of the 6211 2" primary headers.

How well do the 2" primary headers fit?

 

[Hemikiller]

I just looked at Summit and they show the 6210 and a 6211. i updated my post to reflect that. The 6210 must be new, I have a set of the 6211 2" primary headers.

How well do the 2" primary headers fit?

Haven't used them yet, still sitting in the garage rafters.