miss match ports

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denny

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Feb 4, 2017
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The $191 is the price on the link motorheadmike posted. That ad in the link says CNC is an option and the picture they show is a head with EVEN LARGER (but atleast straight) exhaust ports so the picture must be of the CNC head.

Those heads don't appear to be designed for a street car. Even with larger diameter headers I don't see them sealing along the bottom for very long.
thanks for the reply UNGN> got the heads for much less than 191. made a deal with the dealer because he said they were hard to move because of the small valves (1.94 1.50). everybody wanted the trick of the month big valves. there is no cnc work on these heads. i wanted them for a 300 horse mild street motor to build at my retirement. retirement is now here. upon further checking it looks like 1 7/8 primary tube headers will cover well. i'll stop at Jegs today and have them drag a box of 1 7/8 out and i'll measure them right there. my calipers show just a hair less than 1/4 inch at the bottom. i'm gonna run them. my smog heads light weight castings sealed very well on my previous motor measured just a hair over 1/4" sealing area.no leaks and about a 250 horse street motor. my picture taking skills might need to be improved on but the angle of the exhaust ports on this head look the same as my other sbcs heads laying around the garage. not designed for the street, i can't imagine a competition head designed with 1.94 and 1.50 valves today. thanks again for your input. Denny
 

SSpev

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Jan 9, 2017
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Oh my. If you are dedicated to use those heads, I hope the engine is built to suit the purpose. A 388 does not need that size of exh port, but it might be ok if you adapt / customize to get a smaller header to fit. You sure could use smaller headers, bigger is almost never better for headers. Small equals velocity and scavaging. 1 7/8 headers on a 383 means lots of RPM. I run 1 7/8 on 450 plus cubes. The intake size seems to be not bad. Small valves are good. Less shrouding. Without knowing the engine specs I can't give any better advice.
 
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denny

Master Mechanic
Feb 4, 2017
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Oh my. If you are dedicated to use those heads, I hope the engine is built to suit the purpose. A 388 does not need that size of exh port, but it might be ok if you adapt / customize to get a smaller header to fit. You sure could use smaller headers, bigger is almost never better for headers. Small equals velocity and scavaging. 1 7/8 headers on a 383 means lots of RPM. I run 1 7/8 on 450 plus cubes. The intake size seems to be not bad. Small valves are good. Less shrouding. Without knowing the engine specs I can't give any better advice.
thank you for your reply. good news so far, my head port size is 1.45 x 1.45 and speedway has a header that is 1.45x1.45 for my malibu. bad news is i'll have to remove my air box which p.o robbed most of the ac stuff anyway. my next post will how to remove the air box lol. 5500 rpm will be my max which probably will not happen a bunch. that is speedways stepped header (1 5/8 to 1 7/8).as i said before i want a good 300 hp smallblock for street fun. i ran a 10 teen 70 chevelle foot brake bb for about 10 years and it was great and i look forward to hearing the radio these days. my other hotrod is a 71 vette that carries about 10 inches of vacuum at idle, so the mild 388 will be a blessing. engine has a very mild crower solid cam with a edelbrock q-jet with a summit dual plane intake. i ran dominators and hp's for years but always liked the q-jets too. should be fun with the 3:73 gears from street light to street light. thank you for your input and look forward for more. p.s, will also be looking for advice on my 79 mustang 8.8 swap into my bu. heard it's not too bad.
P5250145.JPG
 
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motorheadmike

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Nov 18, 2009
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That exhaust port looks like it wants nitrous.... and lots of it! I'd sell the heads and buy some Vortecs for an easy fit and the ability to make 300hp with proven results.
 
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pontiacgp

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Mar 31, 2006
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Those are rectangle port heads but your headers are for oval port heads....

 
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denny

Master Mechanic
Feb 4, 2017
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That exhaust port looks like it wants nitrous.... and lots of it! I'd sell the heads and buy some Vortecs for an easy fit and the ability to make 300hp with proven results.
not selling the heads and not interested in nitrous, they will be ok for my build. i would not use these for super gas or super comp.
 

denny

Master Mechanic
Feb 4, 2017
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Those are rectangle port heads but your headers are for oval port heads....
header number 917185v flange type square port o.d. 1.63-1.75. port height 1.45 width 1.45. my head port is 1.45 height 1.45 width.i'll go with these. talked with Kirk at speedway about my problem of matching the ports better and he said these were 1.45x1.45 which is the size of my head ports.while checking for the right fit i found that in no way were these ports considered big. i know the velocity stuff vs small ports a little but these should be fine.
 

pontiacgp

blank
Mar 31, 2006
29,270
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Kitchener, Ontario
header number 917185v flange type square port o.d. 1.63-1.75. port height 1.45 width 1.45. my head port is 1.45 height 1.45 width.i'll go with these. talked with Kirk at speedway about my problem of matching the ports better and he said these were 1.45x1.45 which is the size of my head ports.while checking for the right fit i found that in no way were these ports considered big. i know the velocity stuff vs small ports a little but these should be fine.

these do not look like a square port header....

img_0120-jpg.61239


this a square port header on top and an oval on the bottom..

dsc02495.jpg
 
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denny

Master Mechanic
Feb 4, 2017
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That exhaust port looks like it wants nitrous.... and lots of it! I'd sell the heads and buy some Vortecs for an easy fit and the ability to make 300hp with proven results.
The $191 is the price on the link motorheadmike posted. That ad in the link says CNC is an option and the picture they show is a head with EVEN LARGER (but atleast straight) exhaust ports so the picture must be of the CNC head.

Those heads don't appear to be designed for a street car. Even with larger diameter headers I don't see them sealing along the bottom for very long.
hi UNG. the heads you got from motorheadmike from procomp website were part#pce281.1744 my part number is pc3101s mine are 59cc/175cc s/plug. the ones on the website were 64cc/190cc valve dia 1.94 and 1.60. mine are 1.94 and 1.50. totally different heads. theirs and mine are square ports. web site heads were angle plugs mine are straight. i would call mine a good stock replacement new head,which is what i want.
 

motorheadmike

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Nov 18, 2009
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hi UNG. the heads you got from motorheadmike from procomp website were part#pce281.1744 my part number is pc3101s mine are 59cc/175cc s/plug. the ones on the website were 64cc/190cc valve dia 1.94 and 1.60. mine are 1.94 and 1.50. totally different heads. theirs and mine are square ports. web site heads were angle plugs mine are straight. i would call mine a good stock replacement new head,which is what i want.

Just to be clear I went to ProComp's website and picked a set of heads, it was a total rectal pluck that I was even close given that you didn't exactly present all of, or any real, usable facts in your initial post. Kinda hard to give us sh*t for speculating/making educated guesses after the fact.

That being said I sincerely hope they work well for you. It just feels a little back-asswards to buy specific headers to fit a pair of bargin bin heads, to potentially go slower; as opposed to buying quality heads and using the headers you already have and get proven performance. The quality of a cylinder head will ALWAYS dictate the performance potential of an engine, and is the cornerstone of every build.

A quick Googling of the supplied part number gave me better pics and info.

https://www.amazon.ca/dp/B00TJRTBX2/?tag=rippca-20

http://speedtalk.com/forum/viewtopic.php?t=17964
 
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