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Discussion Starter · #1 · (Edited)
I've decided to take a little different route than first planned with my street car. I had a NO/E bracket car (68) and my street car (68). The street car was originally intended on being a very mild 427 to be able to comfortably drive to cruise ins and such. Well, I just sold the race car, so it's time to revamp the street car.

Currently a 9.5:1, .030 over 427. Hydraulic flat tappet, 218/226 @ .050, Performer RPM Q-jet w/ a SMI Q-Jet. 781 heads, 2.19/1.88's port matched to the intake.

What I'm wanting to do with it is, change the heads out for some 270 Brodix Race Rite ovals w/ CNC chambers, bump the compression up one point to 10:5:1 and install a hydraulic roller cam somewhere in the 240 ish range @.050. Upgrading the fuel system and installing one of the Holleys I have laying around.

Now, to the question..... I'd like to get some more flow out of the exhaust side of those Brodix heads. Would it be worth having just the exhaust side ported or just worry about trying to make up with it duration on the exhaust? OR, have the exhaust side ported and still try to get more with duration on the exhaust?

Am I overthinking this?

Looking to have a high performance street car that will be run in a street car class at the track. Not looking for something to make long trips in. Looking for something that'll move that I can still drive on the road.

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I've decided to take a little different route than first planned with my street car. I had a NO/E bracket car (68) and my street car (68). The street car was originally intended on being a very mild 427 to be able to comfortably drive to cruise ins and such. Well, I just sold the race car, so it's time to revamp the street car.

Currently a 9.5:1, .030 over 427. Hydraulic flat tappet, 218/226 @ .050, Performer RPM Q-jet w/ a SMI Q-Jet. 781 heads, 2.19/1.88's port matched to the intake.

What I'm wanting to do with it is, change the heads out for some 270 Brodix Race Rite ovals w/ CNC chambers, bump the compression up one point to 10:5:1 and install a hydraulic roller cam somewhere in the 240 ish range @.050. Upgrading the fuel system and installing one of the Holleys I have laying around.

Now, to the question..... I'd like to get some more flow out of the exhaust side of those Brodix heads. Would it be worth having just the exhaust side ported or just worry about trying to make up with it duration on the exhaust? OR, have the exhaust side ported and still try to get more with duration on the exhaust?

Am I overthinking this?

Looking to have a high performance street car that will be run in a street car class at the track. Not looking for something to make long trips in. Looking for something that'll move that I can still drive on the road.

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i would think with the proper cam for your combo that it should do what you are asking
 

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1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
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I bought a set of Brodix Race Rite 294 R port W/CNC option cut down from 119cc to 115cc with Comp Cams guide plates etc. from Mike Lewis "Wolfplace" at a very good price, get a cam with 10*-12* more split in duration for exh. and Johnson or Gaterman hyd roller lifters (I used Howards Max Effort) or more expensive ones, I also bought Straub roller rockers to help with geometry and centering valve tip to roller rocker Scott Foxwell made a great video about that
 

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Discussion Starter · #5 ·
I guess what I'm asking is, would it be worth the money to have the exhaust side ported? Not sure what only having the exhaust side ported would cost. I think a complete port job is around $1000.

The more air in + the more air out = more power. Porting the exhaust side would lower the percentage loss from intake to exhaust cfm, equaling a better flowing head. Would the cost of the port job be worth the gains or should I just try and make it all up with duration on the exhaust side of the camshaft?

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I guess what I'm asking is, would it be worth the money to have the exhaust side ported? Not sure what only having the exhaust side ported would cost. I think a complete port job is around $1000.

The more air in + the more air out = more power. Porting the exhaust side would lower the percentage loss from intake to exhaust cfm, equaling a better flowing head. Would the cost of the port job be worth the gains or should I just try and make it all up with duration on the exhaust side of the camshaft?

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By the time you buy the Race-rites and port them, wouldn't you be money ahead with a set of BB-1"s?
 

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Discussion Starter · #8 ·
If you want ported race rites I would look here
Not looking for a fully ported set. Plus, I live about an hour from Brodix. My machinist has been close friends with the owners for years and years. He can get me a good deal on a set. Plus, I only need bare castings.

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PS I wouldnt let just anybody port heads. Only **KNOWN KNOWLEDGABLE EXPERIENCED" ought apply!

Me, I'd replace the cam/springs and run it. Keep the LSA tight to help with the 9.5:1. Ensure it can see 6800 rpm safely, valvetrain -wise, which with a hyd roller will require more spring than the ol Isky 8005a. Those springs will hold to around 6000.

EDIT: Maybe consider a small solid roller, depending on amount of street use ( less weight more revs) . 235 @050 intake, which ought get somewhere around 155 @ .200" and 109 LSa.

I dont like to limit 3.76" stroke engine rpm much. They really shine from 6000-7500.
 

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Discussion Starter · #10 ·
By the time you buy the Race-rites and port them, wouldn't you be money ahead with a set of BB-1"s?
I want the exhaust ports in the stock location. They have a BB-3 oval Race Rite, but they're more than a port job expensive than the 270's. Awesome flow numbers though.

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Not looking for a fully ported set. Plus, I live about an hour from Brodix. My machinist has been close friends with the owners for years and years. He can get me a good deal on a set. Plus, I only need bare castings.

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If thats the case I would run them as they are.
Do you already have valves etc?

Do you plan to change pistons to gain comp? Belive smallest chambers from Brodix with CNC is 112cc.
 
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Discussion Starter · #12 ·
PS I wouldnt let just anybody port heads. Only **KNOWN KNOWLEDGABLE EXPERIENCED" ought apply!

Me, I'd replace the cam/springs and run it. Keep the LSA tight to help with the 9.5:1. Ensure it can see 6800 rpm safely, valvetrain -wise, which with a hyd roller will require more spring than the ol Isky 8005a. Those springs will hold to around 6000.
I've got two sets of GM rectangle port heads I'm wanting to sell to fund the Brodix heads and Hydraulic roller. By going to aluminum (the way I'm looking at it), I can bump the compression up (more power) and save half the weight of the old iron heads, plus have a way better flowing set of heads.

I %100 agree as well. If I choose to have the exhaust side ported, it'll be by someone who knows what they're doing.

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Discussion Starter · #13 ·
If thats the case I would run them as they are.
Do you already have valves etc?

Do you plan to change pistons to gain comp? Belive smallest chambers from Brodix with CNC is 112cc.
Yes, I have everything for them. (Valves, springs, etc)

Going to run the same pistons. Going to change it with head gaskets and milling. May not be able to get exactly what I'm looking for. I haven't put it to a calculator yet

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Yes, I have everything for them. (Valves, springs, etc)

Going to run the same pistons. Going to change it with head gaskets and milling. May not be able to get exactly what I'm looking for. I haven't put it to a calculator yet

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Belive you can get them angle machined close to 100cc from Brodix. Brodix machines the mounting holes etc after the milling so brackets still fits.
 
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Does angle milling cause any other fitment issues? Intake, Exhaust manifolds?
 

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Discussion Starter · #16 ·
Does angle milling cause any other fitment issues? Intake, Exhaust manifolds?
They fix all of that when it's angle milled. They realign the gasket surface for the intake manifold and true the head bolt holes up square to the deck.

Exhaust manifolds and headers can pose a problem though.

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Porting the exhaust is a waste of time for non power adder builds. Exhaust is under pressure just like your favorite carbonated beverage....as soon as the valve cracks its out of there.

Cam choice of 240 duration on a hyd roller would be equal to a flat tappet in the 258 duration range. Too much for a 427 with good heads to make power under 7000 rpm.
 

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Discussion Starter · #18 ·
Porting the exhaust is a waste of time for non power adder builds. Exhaust is under pressure just like your favorite carbonated beverage....as soon as the valve cracks its out of there.

Cam choice of 240 duration on a hyd roller would be equal to a flat tappet in the 258 duration range. Too much for a 427 with good heads to make power under 7000 rpm.
That's the answer I was looking for. Thank you, Chris.

I didn't realize there would be such a difference in duration from a hydraulic roller to a hydraulic flat tappet.

I appreciate the response.

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That's the answer I was looking for. Thank you, Chris.

I didn't realize there would be such a difference in duration from a hydraulic roller to a hydraulic flat tappet.

I appreciate the response.

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You welcome. If you need a combination of parts to work let us know. This is 427 with OEM oval heads and my 229/241 camshaft..stock OEM low profile intake...

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