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GM 5.7 305 LT1 Exhaust Manifolds


Guest Anonymous

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Guest Anonymous

AS Mudge pointed out is the "cost factor" of the "ramhorns" he identified. You will need the straight dump and back swept dump with the 2 inch exhaust ports. Then you pay a machinist to angle mill both of them for not less than $50.00. And then you have to grind and trim the exhaust outlets to prevent engine block interference (I have the rams horns on my project for low heat due to a fiberglass hood) I see the "ramshorns" at swap meets with "collector ($) prices". Altogether, you are beginning to look at the price of quality ceramic coated block hugger headers. Summit sells $79.95 painted generic block huggers reportedly made by Flowtec that bolt up quick.Corvette also made a rare as hen's teeth ramhorns with a 2 1/2 inch ports, that I have never heard of a confimed Z fit despite good flow reports after modification. Now if your dip stick is on the passenger side,... you will need a OEM cast iron manifold from a 1980's Camaro,Caprice or a MonteCarlo for the drivers side and cast iron manifold for the passenger side from a 1980-92 Caprice or Camaro to clear the dip stick, but no machinist milling

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Guest 73TPIZ

Guys, i'm running the 2 1/2" center dumps on my '73 w/ 305 and they fit great. My eng mounts are homemade so i can't say how it compares to JTR fit. i think my eng is ~1" forward and a little higher than JTR. I puchased them new from a local dealership for about $100 each. left and right are both center dump but they are different as they have fact brackets on fronts for accesories.

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Don't know why you would want to fuss with the cast iron (those things are as heavy as, well, cast iron) when you can get ceramic coated blockhuggers delivered to your door ready to bolt up and look great for <$200.

 

JMHO.

 

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BTW, I had a cousin from W. Virginia pronounce it Come-mirror-oh.

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I ditched my headers on the Jimmy in favor of the 'vette 2 1/2" rams horns. They seem to make more low speed torque than the headers with no real reduction in high rpm output, I do have a tiny cam, however. I cut my generator mounts off and ran two drivers side manifolds since they were the cheapest. Mine were $78 each from Ecklers Corvette parts. 5 years ago or so there was a 79 'vette in Hot Rod that ran in the low 9's with a Q-jet and ported rams horns. I am really pleased with the manifolds. They significantly lowered the noise level in the engine compartment. I'm going to port another set for my Corvette. Brezinski sells ported iron manifolds and you can have them extrude honed as well. Combined with either a pair of mandrel 45's or a 90 they are a valid option to headers, but may or may not be "bolt-in" to a JTR installation as already noted. The 'vette manifolds are only available straight dump and not angle dump like the recommended manifold. L-79 Novas might have had a 2 1/2" angled manifold, but if so, it is one of those stupid expensive, hard to find parts.

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MIke, have you priced out how much $$$ it takes to have two manifolds Extrudehoned? By the time you pay for the cast iron manifolds, have them hogged out via Extrude, angle mill them, and then have them powdercoated, you could probably have custom headers made for the car--ouch, Baby!! Reason why I piped in here: I originally bought the cast iron manifolds for my engine, but I found cracks in one side AFTER I bought them used :mad: so a return was not an option. I finally broke down (figuratively but almost literally) and bought the Summit block higgers which I have now powdercoated like Dan Juday's. They are lighter, tighter, and look like a fighter :D As far as noise is concerned, I think the mufflers are a better place to concentrate to quiet the car. If Sandersons or some other high quality brand are made available USED to someone in this situation, I would certainly recommend they buy those for the better quality and sealing.

 

Davy

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Aww Guys,

 

Don't make it so difficult, I had just finaly decided for the 10th time, double dare, no going back that I would just go with off the shelf cast iron .

 

Where did you get your headders Dan ? you appear to be very happy with them.

 

I think I still like the cast iron approach, but only if they realy are quieter.

 

Mike

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The cost is ridiculous, but in my Corvette I want it to look all stock. I am planning on running a Performer RPM and will grind off all of the manfs. marks, and sandblast it to return the sandcast look. Then I will machine the front to use the manifold oil fill tube. I want it to look absolutely bone stock and run in the 12's. As you note on the cost, I'll most likely port the 2 1/2" rams horns myself to save $.

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Has anyone used the rear dump LT1 cast iron exhaust manifold? Fit? I know the arguments both ways. I used block huggers on my other hybrid and am toying with idea of cast this time IF they fit nicely without machining...otherwise coated block huggers get the nod. john

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Guest Anonymous

I have currently picked up a TPI for my 350 small block and would like to put a supercharger:D to my tpi dose any one now what would run the best on it.

 

 

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