CHI 3v Heads- Which exhaust system?

How about custom built:

I thought the 3V's could use a std raised port header, and it was just the intake manifold that was limited to CHI or Parker?

quote:

Originally posted by DW:
My 351-C needs to be redone and I want to step up to CHI aluminum heads. I'm told that the 3V-185cc heads will make more power along with better throttle response than their 4V heads.

My concern with the 3V heads is the non-stock exhaust port location and want to avoid exhaust system fitment issues. I was hoping to be able to use off the shelf GTS type headers bolted to GTS exhaust/ mufflers.

Are any of you guys that are running the 3V heads using this exhaust system? Any experience with this system or other recommendations would be greatly appreciated.

Dennis

I used the CHI 2V aluminum heads and a TFC 2V manifold, which looks exactly like the Parker Funnelweb and is also made in Australia. I had no fitment problems with my Big Tube exhuast headers. I can't say what the power output is on the 2V head vs the 3V, but the power is much better from idle on up to 6500 rpm than my old cast iron 4V close chamber heads. I even increased my gas mileage by almost three miles to the gallon and never changed a thing on the carb.

The originl 3V heads flowed slightly less then the 2V heads at low lift. Lift beyond about .4 the 3v flowed better. Your duration below .4 makes it about equal BUT the difference was basically more material around the valve which ...if taken back down to match the 2V would make the 3V better then the 2V at all lifts.

That's the theory anyway. Not sure f the later 3V's were trimmed better.

JFFR,

What mufflers/ pipes are you using? I know the 4V headers will bolt up to the heads ok, but my concern is that if I buy a complete ceramic coated system and then it ends up needing to be heated and tweaked to line up and clear everything properly.

Thanks, Dennis

quote:

I buy a complete ceramic coated system and then it ends up needing to be heated and tweaked to line up and clear everything properly.

Don't know about your location, but coating is not just a vendor option. I have a show car level coater here in Fresno. I just ordered a new set of GTS headers from Quella, uncoated. I'll work out the fitment and THEN get them coated. You might look into doing the same.

Larry

Everything I am doing I am making my own but I am taking the exhaust over the suspension. I can get two larger pipes over the suspension then I could get a single pipe through the sspension. I have been looking at what I am going to the mufflers but I have not chosen one yet. I will be coming back down at an angle and will likely cut into one and bring the pipe into the exhaust canister at a bit of an anle; slightly different.

Sufice to say every aspect will be custom made.

Gary

You guys make a good point. I'll buy the exhaust parts raw and then I have the option to change things before the coating goes on. It's a pain dragging the car to an exhaust shop to have changes made, but it will be worth it in the end.
Thanks, Dennis

> I'm told that the 3V-185cc heads will make more power along with better
> throttle response than their 4V heads.

Which intake are you planning to use? CHI makes the 185cc 3V port
and the 218cc 3V port (now called a 225cc for marketing purposes
since AFR and others make 225cc heads). The intake selection for
the 185cc port is limited to CHI 3V very tall single plane. The
218cc port will mate up to a CHI single plane or Scott Cook's dual
plane. We have one of each here to dyno test.

> My concern with the 3V heads is the non-stock exhaust port location
> and want to avoid exhaust system fitment issues.

The location difference isn't large but some headers are very tight
on vertical clearance.

> I was hoping to be able to use off the shelf GTS type headers bolted to
> GTS exhaust/ mufflers.

The GTS headers did well in our dyno tests but we lost 50HP through
the GTS mufflers. 3" inlet/outlet Magnaflow mufflers got it all
back.

Whatever you do, have an OR bung welded in for
tuning with a wideband.
Dan Jones

Dennis, talk to Will 4NHOTROD he had 3V heads on his black car. his email is wdemelo@cogeco.ca
Richard T.

Dan,
I was planning to use the Scott Cook dual plane intake if I go with the 3V heads. I guess I didn't do my homework and didn't realize that the dual plane isn't available for the 185cc heads.

I want to have the intake system fit under the stock engine cover. It looks like that narrows it down to the 3V-218cc heads with the Cook dual plane, or the 4V-228cc heads with a Blue Thunder or other intake that fits stock heads.

Dan, would you be able to give me a recommendation on which of the above combinations would give the best power band for street use with a stock bore and stroke.

Thanks,
Dennis

Dennis,

Art Stephens is also running the 3V heads in his Pantera. Another member you can contact about the exhaust system.

Hello Dennis,
As George said, I am running the 3V225 aluminum CHI heads with Scott's dual plane manifold, all stuffed under the stock screen. I had previously modified the brackets that support the screen, so I'm not sure if everything will fit without some relatively minor modifying? I suspect that Dan will tell you to go with the 3V's for performance.

Art

quote:

Originally posted by DW:
JFFR,

What mufflers/ pipes are you using? I know the 4V headers will bolt up to the heads ok, but my concern is that if I buy a complete ceramic coated system and then it ends up needing to be heated and tweaked to line up and clear everything properly.

Thanks, Dennis

I am using the PI Big Tubes which were an original Mind Train design and twin glass packs, which are also the old Mind Train design. The headers are ceramic coated and I also installed the exhaust cross over pipe, which is just in front of the rear frame brace. The cross over seemed to pick up the mid range on the engine and it made it sound much better.

I believe the pipes after the headers are 3" dia., but everything does fit the car. What was nice about the 2V CHI aluminum heads is that the headers and exhaust system fit exactly up the same way that the cast iron 4V heads did.

I can't comment on the 3V CHI head for power and header fitment, but the 2V CHI aluminum heads make some much more power than my old system did, it feels like the engine is much bigger than a 351 cubic inches. With my cam, I can turn the engine to 6500 rpm and it is still making power at that rpm.

Thanks to everyone for providing me with lots of information and ideas. Learning what others have done is the best way to find out what works, and what doesn't.

I will be calling CHI again next week and thanks to the info provided by you all, we will be able to work out the best combination for my car.

Dennis

Dennis,

Dan's got my fresh CHI 3V's and matching CHI DP intake.

I have done a lot of e-mailing and phoning this past year, including burning Dan's ears off.

My Longchamp's a heavy car and with custom roller cam the above combo and a good exhaust system I'm aiming for strong low and mid range performance up to around 5500rpm.

Phil
79 Longchamp GTS 3061

quote:

Originally posted by DW:
Thanks to everyone for providing me with lots of information and ideas. Learning what others have done is the best way to find out what works, and what doesn't.

I will be calling CHI again next week and thanks to the info provided by you all, we will be able to work out the best combination for my car.

Dennis

Think about the CHI 2V aluminum head. Edelbrock makes an air gap manifold that is a perfect port match and with a low enough air cleaner, will clear the engine cover screen, but it will be close. You can also use their performer manifold and Weiand makes a nice single plane 2V manifold also. For a good street application, I don't think you need all the flow that the 3V heads can give you and the 2V heads should produce more low end power because they will have better velocity.