Ramshorns or headers?

[3rdGenrationChevyman]

Ive got a stock 307 w/ramshorns, would like to put an exhaust on it to create a little bit of a more aggresive sound,maybe improve my acceleration a wee bit. was wondering... would it be worth it to invest in a set of headers, or would the stock ramshorns be sufficiant? Im not gunna race it or build it into a wildly powerful engine, but a little more pickup & a better,meaner sound would be nice... also Im going to pick up a new carb, was looking at some of the smaller holly`s. which size carb would make sense for my stock smallblock? the carb I have now is pretty rough, Ive rebuilt it but there is still a little hesitation & studdering from a standstill & it jerks at freeway speeds... also the butterfly is pitted up all to heck. I dont want to waste money on a big carb if the rest of the motor wont swing with it. thanks!

[krue]

I would stay with the manifolds. Can't help with the carb. I am just going to have my Q-jet rebuilt and tuned up.

[dregs454]

keep ramhorns - headers rust, leak, cost money, wont make a noticable performance difference. if u want a meaner sound, get different mufflers

[thisolechevy]

On the carb. I would go with Edelbrock, thats all I use and I love em' I have a performance 327 SB and have the 650cfm performance carb. for a stock engine I would use their 500-550cfm they work great

[super-k]

I`d go with the 500+/-cfm.Quadrajet is too much carb for stock 307.I like headers and rams-horns.Headers will give more power and a badder idle sound.I`ve had headers on a`71 since 1989.They were the cheap(uncoated)ones,and the collector gaskets just started leaking.One of the original rams horns blew-out in center where all gases meet.They are the most"header-like"of stock manifolds.The comprimise is gases from the outer ports blow across the center ports to get to the dump.With headers,gases flow unrestricted and then to larger collector(dump).

[72C203503ONTHETREE]

If you use the Edelbrock carb(or Carter carb, what the Edelbrock copied), make sure you use a heat sheild or a phenolic spacer. When the edelbrocks get hot sitting on a hot engine they tend to puke fuel out the vents and flood the engine out. When you come back to start it it takes a while cranking it to clear it out enough to start it. I have had two, both new, that did that and a freind had one on his 55 Chevy that did it even while it was running. Other than that they are great carbs, I just got one for my 72. I do prefer Holley double pumpers or the Speed demons for power and racing though.

[barn9]

Headers, mostly because they are not made of cast iron!

[mrein3]

I'd keep the ramshorns. I never personally saw a set of headers that were worth a crap though lots of folks on this board have sets that work. My engine guy says most over the coutner headers ROB your engine of power because they bleed off too much heat. If headers are so great how come GM didn't put them on at the factory???
For a carb I'd get an Edlebrock 1406. Not too big for that 307. Still big enough if you ever upgrade to a 350.

[crazy longhorn]

I am a big Holley fan, & would reccomend an 0-1850 holley (600 cfm,vac secondairies). If you prefer the Edelbrock carbs, the 1406 should do you. as far as headers, I feel there is power to be gained with a good set. on the 307, i would stick to 1 1/2-1 5/8" primary tubes, for the low end tork. Also, keep the pipe size to about 2", & a set of Magnaflow muffs should have a nice deep rumble. good luck,crazyL

[70ChevyLongbed]

As far as the headers/ramshorns debate... I think it's close, but I'll be switching to headers.

As for a carb, I agree with the suggestions of a 500cfm. A 750cfm is way too big for the 307... IMHO. Edelbrock has a 500cfm and I think Holley has a 570cfm.



Here's the specs on what I did to my 307 last year:

Edelbrock Performer Carb 500cfm (#1404, manual choke),
Performer intake manifold (#2101), Engine Works Cam (#135280H) with 214/214 @ .050 duration and .443/.443 lift, HEI Distributor (new, for stock 1975 350) new plug wires, R46SZ plugs gapped at .045, short water pump, new fan clutch to fit the new water pump, new water pump pulley (two groove), Alan Grove Alternator bracket (#213L - ALT.), new crank pulleys (three groove – and special spacers for the press-on balancer), new detent cable(kick-down), new Edelbrock Elite air cleaner and several bits of chrome… cuz I like it

I already had Flowmasters, which I love the sound of...

[pierce]

A common problem to think about is headers will heatsoak a stock GM starter to the point it may be hard to start back up when hot.

[boraxman]

Headers and 600 vac. Holley.

[3rdGenrationChevyman]

hey, thanks for all the input, guys! that is the carb I was looking at was around a 500-600 cfm, & I was eyeballing the performer intakes... 70chevylongbed, after all that, how does it run? alot quicker? I would like to be able to smoke some imports every once in awhile... BTW, Im drivin a 70 longbed, too...

[Bowtie67]

Headers and spend a little extra for the ceramic coated, they will help keep the engine area heat down and heat on the starter. Carbs, I would go for a 600cfm and the reason would be if you ever swapout the 307 for a 350 it will work better than a 500cfm unit especially if you ever do any mods also if you dont like it you'll have an easier time unloading it because it will fit more applications than the 500cfm unit will. I prefer the Quadrajet carb over the Holleys or Edelbrocks, better fuel economy and better overall performance. Well actually I prefer Fuel Injection best.

[70ChevyLongbed]

Originally Posted by 3rdGenrationChevyman

hey, thanks for all the input, guys! that is the carb I was looking at was around a 500-600 cfm, & I was eyeballing the performer intakes... 70chevylongbed, after all that, how does it run? alot quicker? I would like to be able to smoke some imports every once in awhile... BTW, Im drivin a 70 longbed, too...

Another quick 70 Longbed

It runs great. I can't smoke my tires <yet> but I think that's my rear-end (which I never bothered to check to see what gears I have). It has great throttle response and really pulls when it gets into the cam. I am very happy with the results and think it was well worth the time and money.

I like my loud dual Flowmasters and this combo made the sound even more 'throaty'

Note: I too was planning on doing an intake and carb only, but was convinced by a couple different gear-head friends that without a new cam I wouldn't see much of a performance difference.

Let us know what you decide!

[inline6Bill]

Carb: 600 C.F.M. Edelbrock non-emission model with heat shield spacer.

Intake: Edelbrock Performer

Exhaust: KEEP THE RAMS HORNS !!! Add a good dual exhaust, get rid of the heat riser in the driver's side, and away you go. On near stock engines and street engines you don't see that much improvement with headers IMHO.

Did this to a 307 I had in "Lerch", my 1969 C-20 tow vehicle. Definitely improved performance by the seat-of-the-pants test, and also improved mileage about 20% (10 mpg to 12 mpg). Later swapped in a Goodwrench 350 with this combo when the 307 bit the dust, and it works even better on the 350.

[3rdGenrationChevyman]

I can't smoke my tires <yet> but I think that's my rear-end (which I never bothered to check to see what gears I have).

Thats the good thing about my truck, it does have the 3:73 posi rear end... soon my truck will be beefy, I just put new meats on it- 31`s in the front & 33`s in the back, BFG All Terrain T/A`s shes getting painted flat black with OD green flames...after the motor is comlete, its gunna be a big ugly truck! wait...its already big & ugly. ok, a big ugly truck with huevos that can run over a lowrider! here`s longhairs photoshop rendition of my new paintjob & my new tires...Im friggin stoked this beast is coming together!!!

[jcueckert13]

on my truck i am sticking with the ram horns and i have a holley 4160 650 cfm carb that i need to rebuild

[68speedalert]

Ram's horns all the way.......wait a minute. If everyone decides to stop using headers, there may not be enough old iron horns for me. Hmmmmmm.

I like q-jets myself. DONOT use a 600 Holley with vacuum secondaries. They are junk.

Also a cam will help tremendously. I like the Comp Cams 256 (I think). It really makes a SB Chevy wake up.

Steve

[jimfulco]

A Q-jet is not too big for a 307. If the motor doesn't want the extra flow offered by the big secondaries, they won't open all the way. Pontiac used them on their 215hp 230cid inline sixes in the late '60s.

[3rdGenrationChevyman]

ok, so if I install a new exhaust with flowies or cherry bombs with the stock ramshorns, install a mild cam (like the comp 256), a perf. manifold (like the performer), & a 550-600 cfm carb, I should get a pretty good jump in performance over my stock beast... awesome. Ive got me goals in place! now, anyone have any of the above mentioned parts they wanna get rid of? btw... you guys seem pretty darn knowledgable...whaddaya think as far as a cam goes?

[3rdGenrationChevyman]

how about this one... dur. 0.50- 224-224 , .470-.470 lift... Im lookin at the Comp CamsSB Chevy Magnum 270H - too wild?

[68speedalert]

What CompCams said years ago was that the 256 cam was the largest you could run without a stall converter. If he's go a manual, it could be alright.

jimfulco, you're dead on, at least that's what I've always thought.

Steve