Corvette Ram horn exhaust manifolds

[VegaGT]

Would they choke a 425 hp 400 cid engine or work just decent ?
This is a mild street engine that has a 5500-5800 rpm redline.
Idles at 600-700 rpm all day long and works well. I'm just tired of the crappy headers and their constant exhaust leaks.
Also the engine looks like a stocker, sounds very mild and runs very well through the rpm range !

I was thinking about running 2.1/2" pipes to Y collector with either 3" or 3.1/2" collector with a good quiet muffler and either single exhaust out the back or dual 2.1/2" out the back after the muffler.

[user-612937456]

CHOKE CHOKE CHOKE the torque will not suffer as much but you will knock a chunk off the top end. Maybe 50-75 Horsepower. There are some good aftermarket factory looking manifolds available as a compromise.

http://www.speedwaymotors.com/Tru-Raman ... ,3823.html

http://www.centuryperformance.com/sande ... r-set.html

[cv67]

Get some decent headers with a nice straight thick flange
havent changed header gaskets in 3 yrs
Trying to "port" those things complete waste of time
Air in, air out

[F-BIRD'88]

Take the headers off and dress the flanges with a metal file to make the matting surface flat. (That raised welded bead)
Spray Paint black, file with metal file, sand with a DA, (120) repeat. It will show the high low spots. Especially effective on the collector flange joint.
This makes a BIG difference.

Constant pesky cylinder head exhaust flange gasket failure is a symptom of a over heated exhaust port.
Air fuel ratio is out of wack at cruise. Ignition timing is out of wack at cruise speeds. (lack of vacuum advance, typical).

Get a AFR gauge and correct the carb jetting at cruise.

When either both these are not right the header gaskets get COOKED fast.

Collector flange joints can be cut off and replaced with better V clamp joints (diesel exhaust stuff).

Swapping to good corvette ram horns from headers will give up 10-12% power and torque (typical).

New install headers need about a month of driving to "take a set". Then they don't blow gaskets or loosen bolts any more.

You pretty much need to check snug up the header bolts every few days, when cold, for about a month of driving.

[pamotorman]

cut the flange so the parts that bolts to the head can be tightened down separately.

[bobalattie]

X2 thick flanges, then get the hard aluminum gaskets with the inserts that Earls sells.. 5 years no leaks.. Bassani headers.

[1989TransAm]

X2 thick flanges, then get the hard aluminum gaskets with the inserts that Earls sells.. 5 years no leaks.. Bassani headers.

Those Earls header gaskets work great. I use them on my builds with great success.

[DaveMcLain]

If you want the headers to stay tight and not leak then dump the gaskets and use high temp RTV.

[427dart]

They should be fine for street use unless you are looking for every last HP.
I used a set of those some years ago on a friends 1972 Monte Carlo project I had built a 416 small block for.
Plus....please don't tell the F.A.S.T. racers they can't run 9 and 10 second ET's with ugly heavy cast iron exhaust manifolds!!

https://youtu.be/sK5Z0VH_cEQ

Even a Ford Mustang can do it too!
https://youtu.be/aNzU0IwtvFo

Better shot... F.A.S.T. racing is the BEST!
https://youtu.be/9UcYp3yHw_g

[pdq67]

Imho, Speedways ramshorns look a lot like Ford "Y"-block truck manifolds. That fit our SBC's.

I think that no more than a good port and outlet cleanup will do very well on 2.5" straight down outlet 'Vette ramshorns.

And I do figure that the price is right.

Just make damned sure they clear the frame/subframe!!!

pdq67

[VegaGT]

This is actually in an old Jeep Wrangler that currently has a fenderwell headers and loud exhaust.
I use this Jeep quite a lot so the headers are kind of worn out as well. They are rusty and look ugly. And each time I paint Them the tires sandblast them to bare metal in no time.

I would like to run inside the frame exhaust which at first glance seem to give me choice of exhaust manifolds or block hugger headers. Are the block Hugger headers any better then the ram horn manifolds ?

[rfoll]

The late 70s under the spark plug truck manifolds are larger internally and have a 2 1/2" exit at the collector. 94, 95, 96 Caprice manifolds are said to be very good. They are over the plug with a rear dump.

[ProPower engines]

The late model buick's with the GM sm blk engines used a real nice manifold that hands down is better then the old truck ram horns.
Did some testing and they made more power and did not choke the engine and retain the heat as much.

[Keith Morganstein]

The cast iron header in the links are Sanderson QP1000 and they are pretty good if you want cast iron. Sanderson makes more engine swap and other unusual headers than anyone.

http://www.sandersonheaders.com/headers ... PerPage=99

[pdq67]

The late model buick's with the GM sm blk engines used a real nice manifold that hands down is better then the old truck ram horns.
Did some testing and they made more power and did not choke the engine and retain the heat as much.

PPe,

Please post a link to a picture of the Buick SBC exhaust manifolds if you can. I never knew about them.

Thanks,

pdq67