Sometimes we do things.......just because thats what WE want. Nothing wrong with building a dream...........your way.....because thats something you always wanted. Best of Luck in your adventure.
I would like to hear what your thoughts are on a cam though. Bench racing and throwing around ideas is never a bad thing.
Eons ago, a friend of mine was a mechanic at a Chevy dealership and he got a great deal on a camshaft out of a dragster. Information wasn't nearly as available back then, so he thought this wild cam was really going to perk up his engine. I don't remember what the engine was, or the car....but I'm thinking maybe a 327 in a full size Chevy. The cam was way too much for the engine and it was a total dog. When he tromped it.......nothing really happened. Tried several times from a rolling start. It was like it wouldn't rev up. He held it to the floor and it very very very very very slowly began to increase in rpms. It was so bad that I have to stress that point again. It was like someone was minutely dribbling a few molecules of gas into it. FINALLY.......it hit its power band and there was a quick "blip" of power. He shifted and again almost nothing for a while ...then another quick "blip". I think the car would have trouble completing a 1/4 mile in 30 seconds....maybe even a full minute. I'm not exaggerating. It was terrible. So he (and I) learned something that day. Given the small displacement you will have, its even more critical to get it cammed properly. If you want to enjoy it on the street, I think some added lift with a mild performance but good torque is where to spend your money. Here is a reference I have posted before that gives you some food for thought. I would see what some of the guys actually running a 283 (more of them than 265) are using and compare what they say. I'm in to larger displacement engines so I don't feel I can give you a specific cam suggestion. You should also consider that driving conditions today have a wider speed envelope and you need overdrive gearing for the expressway.....which needs good torque to work properly. Don't want the engine lugging in OD.
I understand exactly where you are coming from. I know you can't just pic a cam because somebody said it worked for them because most people don't know why they picked their cam anyway. It has to be a proper working combo of parts. I have done a lot of searching with 283 builds for just this reason/fact finding. Some are helpful, a good bit are not because most people are stuck in the Glory Days of these engines and don't realize how much stuff is out there now compare to say "power pack" head days and the "097 Duntov Cam". And I'm not knocking Nostalgia but something far more efficient and powerful can be had with more modern parts. The most basic, untouched 305 head is like putting a new set of AFR heads on a 350. I use as many engine formulas I can find and compare numbers. That is one of the reason for my choice to use L98 Aluminum heads. Pound for pound it has everything you want for flexibility and the amount of air a 265 running in the RPM and torque range I'd like it to be in. Everyone says there are better heads but they are usually referring to a 350 and in that case I would agree. Everyone says port them and get all the flow you can. That is not always the best thing and most don't understand that. Port velocity is just as important if not the most important thing. If it's too big, you have dog on the bottom and make power up high. Too small, may make power lower but you can choke you combo of parts too. Check out this article. People dog the 305 too. See what this guy did for an Engine master's compe***ion. he has since added roughly another 100 HP to it's output. I have spoken with him too as he is actually kind of an interesting and knowledged guy on small cubic inch Chevy stuff. I put a lot of his direction to good use in pursuing this madness in my head! LOL ! He has made some other odd things using small engines for power generation, it's interesting. David Kauffung 308 Chevy Small Block Rebuild - Popular Hot Rodding Magazine
I am NOT a SBC nerd. I have read through various builds over the years from boredom, but did not retain a lot. I understand that this is a low buck mental exercise more than anything. However, I do have a couple questions, for my own curiosity and maybe to help guide your plan. What's the piston speed of this combo and at what RPM is it going to be limited by stock parts? I think that with a shorter stroke you can buzz it higher with the same parts. 7K is just a bit higher than some of the stout stock stuff, right? https://www.chevy********.com/news/the-heart-of-a-legend-z28-camaros-small-block-dz-302/ I get that this isn't all the top quality rotating ***embly and if the stock hyd roller cam components are used, that might also set a RPM limit. But you want it to scream. Big inch SBCs can do 7K.
@bfalfa55 In my mind the objective is not HP, at least top end HP.......per se. At one time I planned to build a homebuilt airplane and was comparing engines to use. It came down to either an aluminum block LS Chevy or a Corvair with an aftermarket stroker crank with large fillets. Without going into a lot of details about the conversion, it seemed obvious to me that the formula for calculating HP held the answer ..........for me anyway. HP = (Torq x RPM) /5252 The thing that happens in general is that when you increase HP.............YOU MUST ................................. INCREASE either Torq or RPM because HP is simply a calculation based on these 2 variables. In my case I had to deal with a propeller that was somewhat efficient at 2700 rpms. Above that it created problems because its tip speed exceeded the speed of sound. Now, like changing gearing in a hot rod, propellers can be designed differently (diameter ) but increasing prop speed using a smaller diameter is like using too tall a rear end gear on the street, and increasing prop diameter meant running the motor at a lower rpm and giving up hp/torq. So the trick was to establish a certain amount of HP / Torq that would suit my needs. Since I was locked in on approx 2700 rpms...........the only variable I had was torq. By increasing torq at 2700 rpms I would automatically increase the resulting HP at any given rpm. In this particular scenario a 100 rpm difference made a sizable gain in power. So it was a balancing act to see what I could get ALL THROUGH the rpm range to 2700 rpms. Increasing the torque at all rpms was done by stroking the engine (actually buying a larger displacement block/crank that already came with a longer stroke and bigger bore) Aluminum LS don't lend themselves to boring due to thin cyl liners. Instead of building a 5.3L (appx 327 ) combo, I was going to go with a 7.0L (427) Block and crank. With the airplane, a key point here was the added 100 cu in added no weight....which was critical to the planes balance. My point here is that I could increase Torq all thru the rpm range and the resulting HP at each 100 rpm would increase by increasing torq. In a car, after an engine reaches 5252 rpm then the rpm begins to outweigh torqs contribution. The rpm then takes charge of the resulting HP. I think in driving daily as well as racing.........its more important to consider the power thats going to be available at each 100 rpm level RATHER than having a big number at one rpm. The old .....it makes 500 hp @ 7000 rpms is great for bragging, but you need overall power building thru your operating range to get the best results. Whatever heads you use must fit the valves within the cylinder bore. In my case, I was going to pocket port some smaller heads and use an LS6 intake as they flow pretty well stock and I only need to support maybe 300 hp @ 2700 rpms. Those heads would keep good airflow velocity and I didn't need big valves and big ports. (I also wanted about 9-9.5 compression) Now I think there is a lesson in there somewhere. You are not as rpm limited as I was.........but your midrange will be very important in overall performance. In your case you are limited by displacement, but I feel you still need to find good torq at both lower rpms and above 5252. Thats probably going to limit your top rpm/hp output but make for a good overall combo. I'd look for a cam that probably doesn't turn over 6000 rpms. Performance is a balancing act much like selecting the best gearing. In the end all you can do is build something and see if it performs satisfactorily or if you need to change the cam once you have actual data. Hypothesizing gets you in the neighborhood......but you will still have to give it a try before you really know what works best for you.
I agree with everything you posted. The ultimate HP has never been my concern. Anytime I have researched cam specs in thinking about this build (and as I think I said before I am currently building a 56 265) my concern was always the best and longest consistent torque curve. The goal was/is a strong mid range. Sacrificing some low end and not worrying about screaming RPM into the atmosphere. Since pretty much all cam RPM ranges are based on a 350 chevy, it is easy to correlate where this engines range will be. it is pretty safe to add 500 RPM to the power cure range of any cams specs. Using the LT4 Hot cam as a number, it states 1,800-5,800. In this build it would be more around 2,300-6,300. This is roughly the range I have been looking at. for this kind of build duration at .050 seems to be best from 215ish to shy of 230. The real fun in building any of these 265's is to see what potential can be had using much better modern technology. I can do it without spending a ton of money. And even if some call it a "waste" of money, there are many more nefarious things i could waste my money on ! LOL ! This will keep me out of other trouble and just get me in trouble with the local police station! As far as the other question/concern asked by RodStRace, Stock Eliminator guys running a complete L99 (LT1 based) in a 4500lb. Caprice engine are turning these engines just shy of 7K on stock stuff and they are only racing. They are running 12.80's at 100+MPH. I'm sure the computer controls help there but if they can achieve that running the "Land Yacht" a Caprice is, I'm sure I can come close to that in my lightened up 55 Chevy. My car will be street driven more and raced when I have a chance. My old style block build has to be different because I am relying on a hyd. flat tappet cam, not a roller. I think I can gain a good bit more performance from this idea because I will be using a roller. Also, since I will be using OE styled parts, I have a much lighter valve train than running link bar roller lifters. In your earlier post, you posted the cost of the Hot Cam, which I agree, is outrageous. If I did use that cam, I will find it for cheaper either used or at someone selling it for less. A summit brand OE roller is listed that is basically this cam, actually same lift with 1.5 rockers, and it is half the price. This build idea can take as much time as I need. I already drive 55 with the engine that's in it. I want to get my 56 265 in it and for now will probably run it with an L-79 copy that I have. It's probably not ideal based on the duration but that engine is around 10.5:1. My 55 weighs just shy of 3,100lbs. with me in it. Currently a 3.70 stock style rear end and a 2.64 first gear Super T-10. In the future it will have 4.10 60 Olds rear and maybe some other transmission upgrade but the Super T-10 will be in there first. The best thing about doing this build is the bulk of the parts are dirt cheap or free. The L98 heads I will run on this are already together for the other 265 I have. If I find another pair for cheap, I will snag them in the meantime.
I would have to calculate the piston speed of the combo. While I am currently building a 56 265, original style block, this roller block idea came to me based on having a lighter valve train than using link bar roller and all that goes along with it. The plan was to build it so it works/last in a range being able to use stock parts. I posted this in another thread here but there are Stock Eliminator guys running 94-96 Caprice's with a complete L99 engine running 12.80's @ 100+MPH in that 4,500 pound boat! They spin them just below 7K. I'm sure the computer helps but if they can do that with those cars, my 55 with me in it is 1,400 Lbs. lighter. I should be able to be close to those numbers with the correct gearing and a 4 speed. I'm not worrying about peak HP. A cam that will have the most consistent torque curve in the 2,500-6,500 range is what I am shooting for in both builds. The intake and heads I will use for both are right where they need to be for an engine this size but both builds will be different based on the cam I can or will choose. I am actually opting for making this build the engine I use in the end but I want to get the 56 block built kind of as a test. The 350 in my car is an old build. been beat on for years and it's tired. Yes, I could build that but the 265 seems like a fun challenge and I'm not really spending any money because I pretty much have everything. The 56 265 is a race prepped back up short block I bought from a guy that has a lot of machine work done to it. With the L98 Chevy aluminum heads I will be running and the dome pistons it should be right around 10.5:1. As a starting point, I am most like going to run an L-79 cam to get it in the car and use it as a testing/starting point. That cam will probably be a little soft on the bottom end but it will be interesting to see how it works since these heads and intake are worlds away from tiny old power pack heads as far as valve size and breathing goes. It's all for fun and it's just money but I'm cheap and never spend much money anyway!
I didn't see what your planned rear axle ratio is going to be......... Small engines NEED stiff gears which requires lotsa R's to make up for the low torque numbers.(You already know this I'm sure) Since it will be geared low (high numbers) a camshaft with a tight-ish LSA will give the little engine a helping hand in packing the combustion chambers In addition to more lift a longer time of holding the valves open will help fill the cylinders. True the tight LSA cam (106*--108*) will have a snotty idle and be a little soggy under 2000RPM BUT.... the gears and a lotta ignition timing will make up for that. PLENTY of compression will help too! (made possible by the bleeding off of compression at low RPM). "I think"( and what do I know...I like FoMoCo stuff!) 7000RPM should be the least amount of R's for this little buzz motor ! I remember BITD the little 265s with a flat tappet camshaft would sing-a-song at top end ABOVE 7500 RPM. Anyway......I'll be watching this thread fer sure..... 6sally6 I kinda re-thunk my above post...... Tight LSA 'come-on-quick-and-top-out-quick'. If your goal is 7000 RPM-ish maybe an LSA of 109*-110* would be better. Lotsa duration will require hi-test fuel and 93 octane still may not be enough ! That's what I like about tight LSA's and bumped up CR....low(er) around town RPM without spark knock. You may need to pay extra attention to cam timing (advance/retard a few degrees) and or ignition timing to make this a dual purpose hot rod !
6.5:1 gears and a heavy flywheel. x 9000 rpm clutch dump = Yeeehah! https://youtube.com/shorts/hoDYGRodUO4?si=9YaJ0-F3JILnfB9v
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