ummm.. if he spends that much on an exhaust?.. and IF it's a properly designed system for the rest of the engines configuration?(such as a nice smooth mandrel bent 2 1/4 incher with walker dynomax's).. you better believe it ill be worth far more than just swapping on a $600 intake and carb. Especially since that's THE biggest restriction for that engine in the first place. And the intake swap won't hardly do squat for his mileage like the exhaust upgrade will. To be far more realistic though.. cheap headers, mufflers and 20 feet of pipe shouldn't cost anyone naerly that much if they know how to bargain shop and do a few things in their own driveway. Long before I started fully welding my own exhaust systems, I simply mocked things into place and took the newly cut pipes to the muffler shop to have the ends opened up for simple clamp on installs. Was still far cheaper than leaving the car with them to do all the work.
my I started out with the intake and 600cfm carb swap because I knew I had issues with the stock carb and intake manifold. I gained some performance and much better driveability. After I installed the exhaust is when it really took advantage of the new intake and carb. More cfm in has to have somewhere to go out. I cut off my stock exhaust just past the manifolds and used reducers to hook to the new exhaust. Now I feel my restriction is in the stock manifolds. Headers are next on my list....and heads....and cam....oops there goes the budget build. If you're going to modify, be prepared to modify something else to make it work better.
2 bbl. manifolds... ...carb, intake, heads, cam, exhaust, converter and rear gear. they were matched for the 2 bbl. so they will have to be matched for the 4 bbl. ...got to pay to play...
I say that mod by itself is nothing he would notice (other than the sound). I would like to see some actual dyno numbers comparing a dual exhaust system with stock manifolds, and then the same system with headers, with a 5000 RPM limit. That's not sarcasm; I really would like to see the results for my own educational purposes.
Yep no problem, assuming the springs are up to it, probably 5500 before HP totally nosedives... About 10,000 years ago I had a '64 Galaxie with 2bbl 289 that'd spin to 6K without issues(no I'm not claiming it was still within a reasonable powerband)... I was kinda disappointed when I swapped to a 4bbl 390 with duals and stock it would only turn 5100 before the valves floated... Would not rev higher even if I held it WOT in first gear...
Wish I could help with number printouts for you and I realize not knowing sucks, but being broke while addicted to power will make many of us do odd things through the years(I even tried those damned "torque plus gaskets a few times"..lol).. in hopes that it will be worth the larger effort and small cash outlay. Plus.. on daily drivers that need to be back up and running for work the next day.. small incremental buildups tying back into the stock exhaust system(even with flexpipes on ocassion).. were/are the norm for some of us. I even did it on ocassion to see the various level of gains to be had from each additional mod. Hopefully the OP won't mind our ongoing imbelishments here and it'd be kinda cool to start our own "list all your effective.. and not so efective engine mod's" thread to compare notes. I'll just add a few off the top of my head for now. Some of the gains for these mod's were VERY slight on ocassion, but the fact that there were perceivable gains and engine tuning requirements changed to some small degree also points to the fact that they had to be in the order of at least 3-4 horsepower for the butt dyno to even feel them at all. Most also know that due to actual percentages of change from stock power levels.. smaller 1% gains are much more easily perceived on a sub 200-300 horsepower combo than on a 500+ combo. So, here goes. 1. Stock 4bbl cam swap into 2bbl motor = more power 2. Ported cast iron/AL intake(2bbl or 4bbl) = more power 3. Larger carb(and/or bored and/or modified choke tower) installed(sometimes with the use of adaptors) = more power 4. Full length "header only" swap tied back into stock y-pipe = more power 5. Shorty "header only" swap tied back into stock y-pipe system = more power 6. Custom y-pipe ONLY = more power 7. Muffler swap/s ONLY = more power 8. Larger exhaust tubing diameter from y-pipe back ONLY(no muffler swap) = more power 9. same as above + muffler swap = even more power 10. full on racing type exhaust(as large as 3 inches on little 302 Fords simply because I too was young and dumb once) with larger primary headers/turn downs behind a completely bone stock 2bbl or 4bbl motor = more power in narrower range(with minor losses down low as expected) 11. single plane manifold on stock 2bbl motor.. just because I had one available and was curious about the effect = more power in narrower range(with major losses down low as expected) 12. spring swap(or heavy shimming) ONLY = more power through rev range extension all the time I have right now but there are plenty more. oops. forgot to put the "potential losses of power are possible without proper tuning" disclaimer before that list. Some of these mod's(especially those involving carburetor mods/adaptors) WILL require new spark and fuel curve tuning to improve drivability and power. Which is the main reason why people write things like.. " I bolted it on and the car went slower". One change, especially the larger ones, usually require another for maximizing benefits.
Frank, that stock cam will rev to 5200, but no more. My old stock motor (20 years ago) fell on it's face after 5200 with nothing but a Holley 600 and a single exhaust with a turbo muffler. Don't know what it'll do with a 2-barrel. Bottom line is: for a small budget, the best mods for these stock 302s are a 4-barrel and dual exhaust. That alone "wakes them up" a bit.
lol.. sorry I didn't put er' on the chassis dyno after every little mod I've done through all these many years of trial and error. I can probably guesstimate pretty damned close based off memory if you're really that intrigued by these "low budget mod's". I'm just guessing here.. but your likely not though. Many smarter guys than me have done some, if not all of them at one point or another through the years and many of those tricks come from old street racers and "stock parts restricted" racing classes where cumulative gains are highly sought after. Ever hear of an alternator cut-off switch? Or maybe wiring it into a WOT switch to reduce alternator based parasitic loss during full throttle bursts? My Infiniti Q45 even had a full-throttle AC cut-out built into the TPS/ECM for that very reason. It's not all just voodoo or black magic. And.. yep.. also own a decently calibrated "ass gyrometer" too which I started developing early on in life while sliding around sandy backroad corners at well more than 75mph. Then I started street racing at age 16 long before I even had a license. And aside from being blessed with a few natural gifts.. it also helps to have family and friends based around hotrods and engine building too. Makes the learning curve that much easier and quicker in the long run.
Yes this is definitely not a full performance build, maybe when i grow up a bit (or at least my income grows up a bit) I will do more. I will take care of the exhaust first, and use the hedmans. then i will take care of that carb and i should have a pretty sweet little machine! Now I'm off to research prices Thanks all!
