I have used both OEM and repro HP manifolds, and found the repros to be superior. Two reasons- Originals are most commonly the C7ZZ type, used by the factory in the latter part of 67, and for nearly 20 years over-the-counter. They have a deep notch on the upper left corner of the ports to clear the smog injectors, and are more apt to leak. Functionally, the core support "bungs" on the outside of the OE are also on the inside, right in the radius of four of the ports, blocking optimum flow. Repros use newer techniques, so the bungs are on the outside only, purely cosmetic. Either way, if you port-match your heads to the large HP manifolds, and clean up the roughness or bungs inside the manifolds, they work pretty well.
Does it make sense to use HIPO headers?
- Thread starter sparx
- Start date
I have used both OEM and repro HP manifolds, and found the repros to be superior. Two reasons- Originals are most commonly the C7ZZ type, used by the factory in the latter part of 67, and for nearly 20 years over-the-counter. They have a deep notch on the upper left corner of the ports to clear the smog injectors, and are more apt to leak. Functionally, the core support "bungs" on the outside of the OE are also on the inside, right in the radius of four of the ports, blocking optimum flow. Repros use newer techniques, so the bungs are on the outside only, purely cosmetic. Either way, if you port-match your heads to the large HP manifolds, and clean up the roughness or bungs inside the manifolds, they work pretty well.
How much work to clean these up as mentioned above. I have Edelbrock heads on my 302, I can provide model number if necessary.
Are the hipos CJ Pony or NPD or other good?
EXHAUST MANIFOLD Hi Po Correct in every detail 1964-1973 - CJ Pony Parts, Inc.
Are the hipos CJ Pony or NPD or other good?
EXHAUST MANIFOLD Hi Po Correct in every detail 1964-1973 - CJ Pony Parts, Inc.
65ShelbyClone
Founding Member
I suppose what I was getting at is that there could be quite some variance in the manufacturing. The castings in the article look different than the ones you posted pictures of which look different than the photo on CJ Pony Parts. The outlets are definitely not the same size, either. C6OE log top, D3OE "hipo" bottom left, C3OE log bottom right.
jonfor
New Member
So my quick dumb question is: if I can commit that eventually I am interested in maybe aluminum or ported factory heads and a better “sounding” cam, would the mail-order HiPo manifolds be my weak link in achieving 300-320hp at the crank or +6K rpm’s? I have lowering springs and 60 series tires and my tri-Y’s hang a little too low. I am also on a tight financial budget for the next 2-3 decades.
Also I have heard some rumors that the bolt hole in the re-pop HiPo flanges don’t align properly with the head??
Also I have heard some rumors that the bolt hole in the re-pop HiPo flanges don’t align properly with the head??
C9OE-9430-B and C9OE-9431-B
The only reason they might say that is the 351 had 2.25" outlets, while the HP had 2". This was offset by the odd angle of the LH 351 outlet.
No such weirdness with the HP manifold:
I think I did.
I do not have a total understanding of "porting",how much work would that require?
Porting means you physically remove material from the object in order change the shape of the hole or enlarge it.
I think I paid less then 100 bux to have mine ported to 2.5" and I bought the manifolds for somewhere between 40 and 60 bux including the shipping cost. Thats gotta be less then a brand new set of hipo manifolds and it will out flow them all day.
Edit:
BTW, you might want to go back an reread my post. its #20 in this thread. There was some info in there for the rest of your exhaust system as well.
I think I paid less then 100 bux to have mine ported to 2.5" and I bought the manifolds for somewhere between 40 and 60 bux including the shipping cost. Thats gotta be less then a brand new set of hipo manifolds and it will out flow them all day.
Edit:
BTW, you might want to go back an reread my post. its #20 in this thread. There was some info in there for the rest of your exhaust system as well.
I've never been convinced that the 90° bend on the 351W manifold flowed equal to the much straighter 289HP manifold. If you went for a ride in my 289HP car, you'd stop worrying about the manifolds real fast.
The weak point on the 289/302 was the tiny little exhaust ports, which need to be opened up quite a bit to match the factory design of the 289HP manifolds. I did that with a die grinder- You've already got it covered with your Edelbrock heads.
The weak point on the 289/302 was the tiny little exhaust ports, which need to be opened up quite a bit to match the factory design of the 289HP manifolds. I did that with a die grinder- You've already got it covered with your Edelbrock heads.
No such thing. There was a kinda-sorta Maverick manifold that looked like one, but it was one side only. The matching piece was ordinary straight crap.
The holes in the middle are 3/8", and get progressively larger toward the ends. Hard to see how alignment could be a problem.
Az Pete
10 Year Member
Been quietly following along here as I need need headers or something......The headers are about 3" off the ground.....drag on anything plus the lower tubes are getting damaged. Wondering if the 289 Hipo manifolds would work good. This is not a racer....just a street toy that is driven everyday. I would hate to loose to much usable street power.
I need to clear an AOD also.......This place has several headers but are pricey......New Page 1
Current setup is:
289 CID, rebuilt and balanced.
KB pistons, bored .030 over. 10:1 compress ratio
'69 351w heads (with 10:1 pistons, ends up with about 9.3:1 end compression ratio and runs great on 93 octane)
Edelbrock Perfomer RPM intake
Edelbrock Hi-flow water pump
Comp. Cams Extreme Energy XE262H cam (Duration 262/270, Lift .493/.500)
Harland Sharp roller rockers (with screw-in studs and guide plates)
Double roller Ford Racing timing chain
Flowtech Terminator, full length, ceramic coated headers w/3" collectors
2.25" dual exhaust with H-pipe
I need to clear an AOD also.......This place has several headers but are pricey......New Page 1
Current setup is:
289 CID, rebuilt and balanced.
KB pistons, bored .030 over. 10:1 compress ratio
'69 351w heads (with 10:1 pistons, ends up with about 9.3:1 end compression ratio and runs great on 93 octane)
Edelbrock Perfomer RPM intake
Edelbrock Hi-flow water pump
Comp. Cams Extreme Energy XE262H cam (Duration 262/270, Lift .493/.500)
Harland Sharp roller rockers (with screw-in studs and guide plates)
Double roller Ford Racing timing chain
Flowtech Terminator, full length, ceramic coated headers w/3" collectors
2.25" dual exhaust with H-pipe
65ShelbyClone
Founding Member
Instead of worrying about power losses or ground/power steering clearances, I would just get some shorty headers.
That's why I put "hipo" in quotes. That manifold came off of some late '70s 351W. The other manifold was a log of sorts, but quite a bit bigger and heavier that a normal one. I don't know what any of the parts came from originally. I don't have the log anymore, so here's the "hipo" style one:
That's why I put "hipo" in quotes. That manifold came off of some late '70s 351W. The other manifold was a log of sorts, but quite a bit bigger and heavier that a normal one. I don't know what any of the parts came from originally. I don't have the log anymore, so here's the "hipo" style one:
Az Pete
10 Year Member
I looked at Headman shorties. Really thought about them until I talked with the reps. The combo of the 289/351w heads thru them off and they have no idea if the ones for the '66 289 would match at the ports. Being I did not assemble this engine, I am not sure. Such a headache when the company that has the info cannot look it up to make a sale.....
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