tri-y headers and smaller exhaust system

[77cruiser]

I built these 5 years ago, just had them coated this winter.

Very nice. If you don't mind me asking, who coated them, how much, and are you happy with them?
Im in the process of getting mine sent out and haven't decided who to send them to.

I sent them to Jet Hot. $300 blasted & coated inside too. Haven't drove the car yet.

[77cruiser]

I was going to use an off the shelf header but nothing to fit the Profiler D ports I opted to make my own. Calvin told me to build what I did. Never tried another set when I dynoed it, so nothing to compare them to.

[mtrhead]

I was going to use an off the shelf header but nothing to fit the Profiler D ports I opted to make my own. Calvin told me to build what I did. Never tried another set when I dynoed it, so nothing to compare them to.

That was my point that so many people slap headers on these heads and they don’t texhnically fit right. Surprised Profiler didn’t raise the bolt holes the same as they did on the port

[steve cowan]

I built these 5 years ago, just had them coated this winter.

Very nice. If you don't mind me asking, who coated them, how much, and are you happy with them?
Im in the process of getting mine sent out and haven't decided who to send them to.

I sent them to Jet Hot. $300 blasted & coated inside too. Haven't drove the car yet.

Jim,
they look great,real nice job you done there.

[steve cowan]

I was going to use an off the shelf header but nothing to fit the Profiler D ports I opted to make my own. Calvin told me to build what I did. Never tried another set when I dynoed it, so nothing to compare them to.

That was my point that so many people slap headers on these heads and they don’t texhnically fit right. Surprised Profiler didn’t raise the bolt holes the same as they did on the port

MTR,
i remember that thread,what was your remedy just slot the header bolt holes?
those heads seem like a fairly big exhaust exit compared to the Dart heads that i am used to.

[mtrhead]

I was going to use an off the shelf header but nothing to fit the Profiler D ports I opted to make my own. Calvin told me to build what I did. Never tried another set when I dynoed it, so nothing to compare them to.

That was my point that so many people slap headers on these heads and they don’t texhnically fit right. Surprised Profiler didn’t raise the bolt holes the same as they did on the port

MTR,
i remember that thread,what was your remedy just slot the header bolt holes?
those heads seem like a fairly big exhaust exit compared to the Dart heads that i am used to.

On my 1 3/4” slotted big time. (If you look at the EME photos of That winning engine with them they had to slot the too)
On the new heads (ATK casting). Just made sure roof of pipe wasn’t blocking port.

[Bazman]

With that combo I think you'll be very pleased going down to twin 2.5". Will you run a X or H pipe? Would run better with either. Some found car ran best with 2 into 1 say twin 2.5 into a single 3.5". I've seen a circuit racer pick up 40hp going from twin to a single pipe - but that was at 740hp and a finely tuned set up

I'm going for more velocity too. My remote mount twin turbo LS3 currently uses the old NA race long tube 1 3/4 headers into 3" merge collectors that step down to 2.5" back to the turbos. They spool too slow, so I'm going to ditch the headers and swap on LS7 manifolds to 2.5" then 3 degree reduction down to 2.25" each side. There's guys making 1500hp on twin 2.25" pipes into turbos, counter intuitive but true. Sometimes velocity is more important than flow.

For NA a low back pressure twin 2.5" system can support 450hp just fine

[steve cowan]

With that combo I think you'll be very pleased going down to twin 2.5". Will you run a X or H pipe? Would run better with either. Some found car ran best with 2 into 1 say twin 2.5 into a single 3.5". I've seen a circuit racer pick up 40hp going from twin to a single pipe - but that was at 740hp and a finely tuned set up

I'm going for more velocity too. My remote mount twin turbo LS3 currently uses the old NA race long tube 1 3/4 headers into 3" merge collectors that step down to 2.5" back to the turbos. They spool too slow, so I'm going to ditch the headers and swap on LS7 manifolds to 2.5" then 3 degree reduction down to 2.25" each side. There's guys making 1500hp on twin 2.25" pipes into turbos, counter intuitive but true. Sometimes velocity is more important than flow.

For NA a low back pressure twin 2.5" system can support 450hp just fine

i was not planing a X or H pipe i am sure i read where C Elston does not recommend it in a drag race style application - i could be wrong ??
as far as street driving,i only idle around so for me it is trying to get best bang for buck on the drag strip.when i do upgrades later in the year i want to be around 500-510hp,i am confident the 1 5/8 header can support that but mufflers at 2 1/2'' might be a concern so may have to step up to 3''.
appreciate your input

[77cruiser]

I was going to use an off the shelf header but nothing to fit the Profiler D ports I opted to make my own. Calvin told me to build what I did. Never tried another set when I dynoed it, so nothing to compare them to.

That was my point that so many people slap headers on these heads and they don’t texhnically fit right. Surprised Profiler didn’t raise the bolt holes the same as they did on the port

MTR,
i remember that thread,what was your remedy just slot the header bolt holes?
those heads seem like a fairly big exhaust exit compared to the Dart heads that i am used to.

I used flanges that were for Fast burns, but still had to adjust them just a little.
I can't remember the measurements, but they are generous.

[cjperformance]

With that combo I think you'll be very pleased going down to twin 2.5". Will you run a X or H pipe? Would run better with either. Some found car ran best with 2 into 1 say twin 2.5 into a single 3.5". I've seen a circuit racer pick up 40hp going from twin to a single pipe - but that was at 740hp and a finely tuned set up

I'm going for more velocity too. My remote mount twin turbo LS3 currently uses the old NA race long tube 1 3/4 headers into 3" merge collectors that step down to 2.5" back to the turbos. They spool too slow, so I'm going to ditch the headers and swap on LS7 manifolds to 2.5" then 3 degree reduction down to 2.25" each side. There's guys making 1500hp on twin 2.25" pipes into turbos, counter intuitive but true. Sometimes velocity is more important than flow.

For NA a low back pressure twin 2.5" system can support 450hp just fine

i was not planing a X or H pipe i am sure i read where C Elston does not recommend it in a drag race style application - i could be wrong ??
as far as street driving,i only idle around so for me it is trying to get best bang for buck on the drag strip.when i do upgrades later in the year i want to be around 500-510hp,i am confident the 1 5/8 header can support that but mufflers at 2 1/2'' might be a concern so may have to step up to 3''.
appreciate your input

Steve, up around 490 nahp you get into the area where the 2.5 dual is small but will still work fine (for way higher aswell) IF everything is setup to work with that size exhaust. Your system will be short so were not talking out to the rear bumper and all the possible restrictions that need to be worked around so thats in your favour.
Youre keen to experiment so you will find what is best with the combo you have. I dont know your cam spec but if you get to a point where nothing improves it you 'may' need to consider a cam swap. I guess im saying that with around the 480/500hp level you have no problems with dual 2.5 unless something is quite wrong.
Cheers,

[Olds455]

That was my point that so many people slap headers on these heads and they don’t texhnically fit right. Surprised Profiler didn’t raise the bolt holes the same as they did on the port

MTR,
i remember that thread,what was your remedy just slot the header bolt holes?
those heads seem like a fairly big exhaust exit compared to the Dart heads that i am used to.

On my 1 3/4” slotted big time. (If you look at the EME photos of That winning engine with them they had to slot the too)
On the new heads (ATK casting). Just made sure roof of pipe wasn’t blocking port.

How are those ATK cylinder heads? Are they an ATK casting or just something they sell? I looked into them the last time I replaced the engine in my daily driver but couldn't convince myself to pull the trigger, so I bought a new engine from GM instead.

[steve cowan]

With that combo I think you'll be very pleased going down to twin 2.5". Will you run a X or H pipe? Would run better with either. Some found car ran best with 2 into 1 say twin 2.5 into a single 3.5". I've seen a circuit racer pick up 40hp going from twin to a single pipe - but that was at 740hp and a finely tuned set up

I'm going for more velocity too. My remote mount twin turbo LS3 currently uses the old NA race long tube 1 3/4 headers into 3" merge collectors that step down to 2.5" back to the turbos. They spool too slow, so I'm going to ditch the headers and swap on LS7 manifolds to 2.5" then 3 degree reduction down to 2.25" each side. There's guys making 1500hp on twin 2.25" pipes into turbos, counter intuitive but true. Sometimes velocity is more important than flow.

For NA a low back pressure twin 2.5" system can support 450hp just fine

i was not planing a X or H pipe i am sure i read where C Elston does not recommend it in a drag race style application - i could be wrong ??
as far as street driving,i only idle around so for me it is trying to get best bang for buck on the drag strip.when i do upgrades later in the year i want to be around 500-510hp,i am confident the 1 5/8 header can support that but mufflers at 2 1/2'' might be a concern so may have to step up to 3''.
appreciate your input

Steve, up around 490 nahp you get into the area where the 2.5 dual is small but will still work fine (for way higher aswell) IF everything is setup to work with that size exhaust. Your system will be short so were not talking out to the rear bumper and all the possible restrictions that need to be worked around so thats in your favour.
Youre keen to experiment so you will find what is best with the combo you have. I dont know your cam spec but if you get to a point where nothing improves it you 'may' need to consider a cam swap. I guess im saying that with around the 480/500hp level you have no problems with dual 2.5 unless something is quite wrong.
Cheers,

thanks Craig,
cam at the moment comp SFT CS 270B-6
235-242 @ 0.050''
270-280 @ 0.020''
500'' lift 106 LSA 106 ICL
timing events @ 0.050''
inop- 11* BTDC incl - 44* ABDC
exop - 47* BBDC excl - 15 * ATDC
i have just fitted 1.6 rockers on the intakes only,different set of springs 420 LBS/IN spring rate on the intakes.testing this weekend.i have taken lash into consideration to keep seat to seat the same,i did not measure cam profile with degree wheel with the 1.6 rockers,i hope i can keep control as this lobe is a circle track lobe and i have talked to a couple people said the cam might eat itself we will see i guess.
i have a couple of cams to try when upgrades occur. comp SFT 244-252 @ 0.050'' 560'' lift 110 LSA
howards roller 242-248 @ 0.050'' 580'' lift 108 LSA still plenty time to consider and plenty more to test and tune before end of the year,full cam timing sweeps,2 other carbs,as cast victor jnr,ported victor jnr,team G intake,4 hole tapered spacer.................
oh and new tri-y headers and smaller exhaust.
Tony sent me a text today of a Holden 383 he just freshened and dyno figures using tri-y and 2 1/2'' collectors
torque curve nice and flat from around 4000 rpm to 5200 rpm 465-470 ft/lbs
480 peak hp,real basic, nice, well built street engine very impressive.

[cjperformance]

Mate you'll be wearing out spanners with all that gear to test good work.
It will be great to see the progression of the combo one cam to the next along with all the tuning variables.
What convertor and rear suspension setup do you run?
Yes great figures from Tony's 383 you mention, thats well built street muscle for sure. Im keen to see the hp figure on his Jzed holden 6, i think he is trying to outgun my little 179 turbo 6 with it ... im sure it will awesome piece the jzed head and im not often impressed by a holden 6! Lol

[mtrhead]

MTR,
i remember that thread,what was your remedy just slot the header bolt holes?
those heads seem like a fairly big exhaust exit compared to the Dart heads that i am used to.

On my 1 3/4” slotted big time. (If you look at the EME photos of That winning engine with them they had to slot the too)
On the new heads (ATK casting). Just made sure roof of pipe wasn’t blocking port.

How are those ATK cylinder heads? Are they an ATK casting or just something they sell? I looked into them the last time I replaced the engine in my daily driver but couldn't convince myself to pull the trigger, so I bought a new engine from GM instead.

I like them. They are Profilers with smaller exhaust ports that are centered relative to the bolt holes (not raised) I feel they should of spent a little more time on the front and rear exhaust ports. They made those slightly wider than the center two. Maybe it was to balance flow as cast relative to the others. I wonder if that was the best as cast shape versus making slightly taller? Either way they fit headers much better and the advertised flow isn't much less than the Profiler D port. Mine are ported so at the end of the day they flow plenty for my 410"

They also have an oil drain back slot running the length of the top deck. The spring pockets also have an oil channel. My profiles held lots of oil in the base of the spring pockets and the valve cover valley. I actually machined my profiles once because of this and I know others have too. ATK took care of that

[KnightEngines]

Got a bad boy 383 Holden going on the dyno in a couple of weeks, 269/272 on 108 solid flat cam, 12:1 pump fuel street motor.
Heads are COME 590 alloys, which I'm not that keen on, chamber sux, but I did get them flowing plenty 296/207 @ .650". Ex port is a little lazy, but sizing is good & it's stable.
We'll see how much the chamber hobbles it, with a set of my iron heads it'd go 580-590hp (maybe a tad more) @ 6800-7000rpm.
I've got some pacemaker 1 3/4" primary tri y pipes here to cut up for it, leaving the 2" secondaries & just adding 3" tuned collectors so he doesn't have to bolt up collector extensions for racing, just drop the pipes, bolt on the slicks & go.