Header choices for 18 SBC in a '69 Nova [Archive] - Chevy Nova Forum

: Header choices for 18 SBC in a '69 Nova


chevy406
18th-March-2009, 12:51 AM
I am about to pull the trigger on a set of TrickFlow 18 heads, but I want to make sure I know how much a pair of 18 headers are going to cost. Can I just modify my current 23 Super Comp headers by cutting off the flange and changing to a Stahl flange?
Who makes 18 headers for the third gen Novas?

levisnteeshirt
18th-March-2009, 11:40 AM
hmm ,,, wonder if these would fit ,, i'd say a set made is gonna be pretty expensive , might have to remove the inner fender ,,

http://www.racingjunk.com/category/1251/Exhaust_Headers/post/1423157/dynatech-18-degree-headers.html

on their web site , they list headers for a 68-72 Nova stepped , 1 3/4- 1 7/8's .. i bet they would put a 18 degree flange on 'em for ya
http://www.afabcorp.com/AFCO_Dynatech_USbrake/merchant.mvc?Screen=CTGY&Store_Code=Dynatech&Category_Code=dragsbMuscleMAXX68_72Nova

chevy406
18th-March-2009, 02:35 PM
Really appreciate the Dynatech link. The 3/4" to 7/8" step design in ceramic coating would work well for me, and the price isn't too crazy. The ones listed in racingjunk look like they would stick out from the head too far for the Nova.

I am slowly getting my build finalized in my head. Right now I just have a used Dart Little M block (4.125" bore w/ 350 mains) and 6" Oliver rods. My plan is to bore it to 4.155" (the bores are acceptable, but might as well start out fresh), buy a 3.875" crank, buy a set of Trickflow 18 heads that I am currently looking at, and then spec out some pumpgas / nitrous friendly pistons plus a solid roller cam grind. My desktop dyno program estimates mid to upper 600s FWHP, depending on how much duration I pick for the cam. This will be a nice upgrade from my current 406, which probably is at 500 fwhp or slightly less.

6NOVA4
18th-March-2009, 04:19 PM
A motor like that needs some 1 7/8" primaries to start with. Maybe do a stepped header 1 7/8" to 2" with a 3.5" collector. Check with Lemons headers out of Paso Robles, Ca. He builds alot of heads up street car shootout type stuff. Nice work and reasonable prices.

Little Red Wagon!
18th-March-2009, 05:32 PM
Just for FYI. I am reusing my 23* step header's. I am going to use some(forgot what you call them)adapter's that change the bolt pattern to the bolt pattern on my bowtie head's. I checked and they are different.

blown67
18th-March-2009, 07:59 PM
I agree with 6Nova4. Lemons makes nice stuff that fits and you can get to everything. I had a set of headers built by Tom Dawson out of Lake Perris, on my 70 nova. I was running a 421 inch sbc with 18* Edelbrock heads. They were 2 inch stepped to 2 1/4 with a 4 inch collector and collector mufflers. We thought they were going to be too big, but they worked fine.

RadialNova
18th-March-2009, 10:12 PM
I got a 69 Nova and it has a 15degree spread port head on a sbc, I bought hedman headers 1 7/8 stepped to 2" with a 3 1/2 collector, they were made to fit a stock front subframe, they fit perfect, no clearence issues with them. I think they were $600-700 uncoated. If you want I'd look and see what hedman has too.

1bad2
22nd-June-2009, 11:23 PM
Just for FYI. I am reusing my 23* step header's. I am going to use some(forgot what you call them)adapter's that change the bolt pattern to the bolt pattern on my bowtie head's. I checked and they are different.

Are you using the Nimac HS7 adapters?
I am in the same situation with some Bowtie 363 18 heads, and in a real bind.
I have a set of Hedmans Fenderwell 1 7/8 that have been coated, and I've been told that once coated they cannot be welded.
Otherwise I would put a set of 18 flanges on them.
I have a set of the 18 to Stahl adapters but my headers are the 23 Stahl pattern and not the spread port pattern.
It looks like with a little bolt hole modification and porting of the adapters they would be real close.
Have you tried them yet?

bowtie0069
23rd-June-2009, 10:21 AM
My desktop dyno program estimates mid to upper 600s FWHP

My 410" makes 615 h.p. with just under 12-1, and a little 260/268-.615/.617 roller. I'd think with 18 heads you could make close to 700 without too big a cam. My Jack Davis headers are 1-3/4"--1-7/8"--2.00" w/3-1/2" collectors; Jack makes them for 350 stock eliminator applications..he likes em big, but I opted to stay with the smaller ones.
I don't see why the flanges couldn't be changed; if they are coated, grind off the coating before welding.

ERV JR
23rd-June-2009, 04:06 PM
as said before the headman spreadport will work. we used a set of headers that were on a old w/s car and put them on the l/s car . the w/s car was a 18 deg and the l/s was a 23 deg.