Ok the only other option to gain Hp is super high compression that's no good for pump gas.... No offence intended... I do have iron head engines here that make great power but without high compression or boost they are low performance engines.
Not everyone is going to wait for heads that won't be out for atleast another year , and then there's the cost of heads vs doing a valve job with some porting spend 7-900 vs 2600 or more. And not all of us have a pile of ported 10 second engine heads laying around.
I looked at it and if you use 93 octane gas and you want 101 octane you have to add 4 oz. of the concentrate race gas to each gallon of gas to get to 101 octane. It is 29.00 for 32 oz of concentrate. So you need 80 oz. of concentrate to get 20 gal of 93 to get to 101. So 60 bucks in concentrate and 60 bucks of premium pump at 3.00 per gal could be $120.00 for a tank of 20 gal. So now if you can find race gas at 7.99 per gal and add the premium pump 10 gal of each the cost is close. 110 race gas can be found from 7.99 to 12.00 per gal depending on where you go. Is it cost effective? Premium pump goes from 2.60-2.90 a gal here in Ohio. I am sure if you mix 1/2 race gas 10 gal with 10 gal of premium pump you get around 100 octane. Have to weigh it out and give it a good look but it is a good alternative if you cannot find race gas in your area. I myself run 5 gal of 110 race gas and 15 gal of premium pump BP. The BP premium pump is supposed to be Amoco from what the pump says.
Also to consider is the fact that you can carry around a concentrated bottle of race fuel additive much easier than multiple gas cans in your trunk for mixing, should you venture too far away from your source. I used to use an additive (not the '104 octane boost' type stuff) that added a couple octane points (not tenths of points) back when I thought my Buick 430 had an actual 10.25:1 compression ratio and the highest grade of pump fuel was 93 octane in Georgia. Turns out it ran just fine on the 93 with its actual 9.4:1 comp.
More thoughts on octane requirements: in addition to the previous advice, using a cam that doesn't have too much overlap, in addition to exhaust manifolds, will reduce scavenging and keep cylinder pressure more predictable, which means you could go a bit higher on the compression ratio and still get away with a particular grade of fuel. You can still make good power this way, as the compression ratio is then your primary means of cylinder pressure (as opposed to higher VE's or scavenging at higher RPMs). As long as you took care of combustion chamber hot spots, you'll be able to run higher compression on lower octane. There are, of course, a myriad of variables that contribute to combustion detonation, so while all this stuff is good general advice, results may vary from combination to combination. In the end though, lower compression, higher VE and scavenging will always make more power (at higher RPMs) than bumping static and dynamic compression and choking off cylinder fill (when considering street-friendly fuel requirements). It's just another method for building power.
Yes, somewhat, but I was referring to changing the physical parameters of how the heads obtain their flow (increasing CSA, decreasing lower RPM velocities, etc.), vs just a basic head clean up job that smooths over sharp spots/rough edges and maintains the original design outside of that.
I thought that's what you meant but I couldn't pass it up. I had a common example in mind when I was begging for that clarification, but it isn't typical to a sbb head to this extreme... Most aluminum aftermarket heads fall quite short on the flow bench from ....magazine CFM numbers. Not sure if they are cherry-picked for a reason or if the term 'lightly massaged' is loosely applied here. Forget corrections, geography, any of that....they simply fall short. Isn't that a surprise? It is not uncommon to get it all back and then some without drastic changes to the port's CSA. This illustrates what you had in mind AND what I wrote about their behavior. Keep in mind that 5cc in a port can be tough to carve depending on where it is, so 'light massaging', 'ton of work', 'slight change in CSA' can seem conflicting. Sorry for the tangent!
Can't seem to edit, but a common one is that many sbc heads having 180-190 cc ports start at 215-220 cfm and end up in the 290-318 cfm range without huge CSA change. No doubt that would change behavioral characteristics as well as allow a radical change in power level. A 250-270 cfm sbb head compared to stock would definitely be as good of an example as any.
I guess the terminology can be a bit misleading. Smoothing things over and leaving everything else in tact would improve things, but I'm not sure how much in terms of CFM numbers (10-15...20?), and I suppose it would change the behavior a bit, moreso in the amount of power the engine now produced more than its powerband potential, though that may be altered a few hundred RPMs or so...maybe. I'm talking a Buick head though. I was just trying to encourage people to do some home port work, but not to go crazy with it. You can ruin a set of heads if you go nuts and port it wrong. Just smoothing things over (removing casting imperfections, contouring jagged or rough spots in the bowl, smoothing over the valve guide ridge, etc.) should be pretty safe for a novice, as long as they have some decent general idea on how things are done. A healthy amount of mechanical inclination helps too. Heck, I can do this stuff, and I'm not a pro. I'm more inclined to listen to the pros though especially in areas that require some finesse or an experienced touch outside of my own abilities, and I'd encourage others to do the same.
It's surprising the where the little things and how they affect are vs major changes in contouring elsewhere and it's seemingly little effect. A VJ worn or beat up from a roller cam for a few years loses 10-15 cfm, and potentially double that # in hp if the demand for the airflow is there. A typical 3 angle VJ's geometry with the seat OD shy of the valve's OD by .020-.030" on diameter can hold back more than 20 CFM due to the valve overhanging the opening and the throat % being small, on a really efficient port. The best possible VJ, bowl and guide contouring won't mean much if further up the line at the pushrod pinch is choked. That's where it pays for expertise. Do the time consuming, labor intensive manifold stuff yourself. There's enough FAST class, stock looking, manifold breathing examples to prove that a combination of both expert and DIY can be effective.
Heading back to the original post: Large factory outlet manifolds- Electra/Lesabre 79-80 Estate Wagon 78-79 Bonneville/Catalina 80 These manifolds require gaskets as they don't have a "ball flange" cast to the outlet. Your casting number search should be: 1246656 RH 1246669 LH I have had to hunt for correct donut gaskets that keep from blocking the outlet diameter to almost nothing. They are still being made. I have no idea if they make any difference in performance. From personal experience I have had two of my jalopies have the cast ball flange wear from loose exhaust and then I was screwed from not having enough talent or resources to be able to repair them. But I am very happy with what I have now- no leaks for a long time! And no fumes on the inside like some of my other junk! Just tryin to help.
