mamba_888 Posted February 18, 2007 Share Posted February 18, 2007 Hello everyone... I am wondering if you guys could share your knowledge. What HP gain does one get from stroking a SBC 350 to 383??? Now, I don't want you to think I didn't think about all the other factors that an engine may make using better cams, heads, etc. These certainly are considerations but they add to the money part as well. I know that my question may sound incomplete but all I wanted to know is really how much one gets from just a straightforward basic stroker build can get in HPs. The reason I ask is that I've researched and found that to stroke to 383, the kits (SUMMIT, SCAT) etc, average to say... $1000.00. For this much money, how much HP does one gain? I just want to calculate the HP bang for the big bux one spends. Is it worth it to stroke and SBC up? Thanx. Quote Link to comment Share on other sites More sharing options...
Guest Mike Posted February 18, 2007 Share Posted February 18, 2007 Ask Grumpyvette to chime in. He's a 383 whizz. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 18, 2007 Share Posted February 18, 2007 a 383 has aproximately 9.5% more displacement than a 350 a 383 has aproximately 7.7% longer stroke if built with all other parts needed being identical (except naturally for the stroke related changes) your compression with the same heads and a flat top piston will be aproximately 0.6 higher IE a 9.2:1 will become a 9.8:1 if everything were to remain the same efficincy wise , thats equall to about a 40hp/40 ft lbs MINIMUM gain over a similar 350, but most engines if cammed correctly see more like 50 PLUS hp due too, both the higher compression and the lower rpm power peak and usually wider tq curve, plus the more effective flow curve in the ports , increasing the cylinder fill efficiency (provided the cam, compression and header scavaging are close to matching) ITS almost ALWAYS a good idea and it ALMOST ALWAYS makes the car noticably faster with street compatable gear ratios now that might not sound like a big gain...but in a correctly assembled engine its VERY NOTICABLE, cracking the 500hp barrier with a 383, is noticably easier than with a 350 just some info YES THE HEADS CAM AND COMPRESSION YOU SELLECT MAKES A HUGE DIFFERANCE IN THE POTENTIAL POWER... SPEND AT LEAST 40% OF THE TOTAL ENGINE COST ON HEADS and RELATED WORK...190cc-210cc port size is the range you want http://www.bracketmasters.com/small_block_stroker_383_cu.htm http://www.chevytalk.org/fusionbb/showtopic.php?tid/131229/ http://www.diabolicalperformance.com/diabolical383.html Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 18, 2007 Share Posted February 18, 2007 another way you can look at this is a well tunned PERFORMANCE engine with decent heads and cam, should produce between 1.2 and 1.25 hp per cubic inch of displacement 350 x 1.25=437hp 383 x 1.25=479hp Quote Link to comment Share on other sites More sharing options...
HICKL Posted February 19, 2007 Share Posted February 19, 2007 I've made no Dyno pulls yet, but have just done what you speak of and am quite pleased with the results. Noticably more grunt and mine revs like a 283 which I didn't think would be the case. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 19, 2007 Share Posted February 19, 2007 "Noticably more grunt and mine revs like a 283 which I didn't think would be the case" stroke and displacement has LESS effect on the engines ability to rev than most people expect, if you have a correctly matched port size cam and compression ratio even a 572 bbc with the correct solid lifter cam reves like a 283, thats why I get fustrated when guys insist on building a 302 or 327 vs a 383-or 396 sbc, while its true the stroke may limit your upper rpms to a lower level youl still rev very quickly and the extra displacement makes the car accellerate faster Quote Link to comment Share on other sites More sharing options...
mamba_888 Posted February 19, 2007 Author Share Posted February 19, 2007 Grumpyvettte... I thank you for the explanation. I did some research amont other forums and they have averaged from between 40/50 hp gains like you've predicted. The bang for the buck = $20/$25 per hp gain. I guess that's not really bad. Quote Link to comment Share on other sites More sharing options...
Michael Posted February 19, 2007 Share Posted February 19, 2007 The best reason to do these kinds of upgrades is if you're doing a rebuild anyway. That is, if replacing the bearings, rings, etc. - and especially if upgrading to an aftermarket rotating assembly, or if pondering a rod resizing/crank grinding job - then that's a good opportunity to upgrade to a stroker crank. The justification is quite a bit more tenuous if the 350 is already running strong as-is, and you're just contemplating a stroker upgrade. Quote Link to comment Share on other sites More sharing options...
mamba_888 Posted February 19, 2007 Author Share Posted February 19, 2007 The best reason to do these kinds of upgrades is if you're doing a rebuild anyway. That is, if replacing the bearings, rings, etc. - and especially if upgrading to an aftermarket rotating assembly, or if pondering a rod resizing/crank grinding job - then that's a good opportunity to upgrade to a stroker crank. The justification is quite a bit more tenuous if the 350 is already running strong as-is, and you're just contemplating a stroker upgrade. Agreed! Like anything else though, one has to weigh the consequences of action or inaction both of which will have consequences. I am just doing my homework and ask the experts in this forum that gives me better insight as to my next step. I already have a 350 from a Monte Carlo I bought for $700 dollars. It's in so-so shape which means I am going to rebuild before I stick in onto my 240z. Now, my enigma is how much engine to rebuild. Well, I was thinking of a 383 stroker with a carb'ed twin turbo and then... ...Grumpyvette and the word stroker woke me up to realities! Such as, why would I stroke (which is for compression and intake gain) when I am doing a turbo job! And why spend $1000 dollars on a stroker) which is counter productive when I need to lower my compression. Thanx again for the insights... I love this site! Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted February 19, 2007 Share Posted February 19, 2007 Well, IMO you can't really just say that you gained 40hp from stroking an engine. In fact you should have a significant increase across the board. This is referred to as area under the curve. Even though you may have only gained 40 peak hp when you apply that across the board you have made a huge increase in power and speed. For example say you have a 283 and a 383 that both make 400hp. The 383 will make a lot more torque and the hp spike will be flatter because it doesn't really have to rev up to get into its power band. The 283 will probably have to get to say 5k rpm before it comes alive and depending in where it shifts it will keep getting into lower rpms where it is not as powerful. With the 383 shifts don't really have the same effect. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted February 19, 2007 Share Posted February 19, 2007 Why would I stroke (which is for compression and intake gain) when I am doing a turbo job! And why spend $1000 dollars on a stroker) which is counter productive when I need to lower my compression. Thanx again for the insights... I love this site! You should ask the people on here who have twin turbo'd 383s.... Compression is all relative to your pistons, cam, and heads. You pretty much have to replace the pistons and cam so really your compression is up in the air. Stroking the engine would hardly be couterproductive. With the turbo'd application that you're planning on building you would be foolish not to stroke the engine since you're going to have to replace the rotating assembly anyway and have it balanced. If you don't replace the rotating assembly a twin turbo'd STOCK engine won't last maybe a few runs. And you will notice the difference in the finished product. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted February 19, 2007 Share Posted February 19, 2007 look youll sellect the correct FORGED DISHED pistons, crank and rods for a TURBO APPLICATION , and get the desired compression ratio, thats NOT an issue, the fact remains that the longer stroke and larger displacement will produce more power and more tq at a lower average rpm than a 350 even with a turbo Quote Link to comment Share on other sites More sharing options...
dustin280zx Posted February 19, 2007 Share Posted February 19, 2007 read this. http://www.turbomustangs.com/smf/index.php?topic=69962.0 and then search and read more on that board. LOTS of great information and things most poeple would think would be unbleivable like a stock truck engine w/140K running 9.50's with 20# of boost and a shot of nitrous that holds together. Those guys on that board know how to build horspower for cheap and some build UNBELIEVABLE HORSEPOWER for expensive like this guy http://www.turbomustangs.com/smf/index.php?topic=77283.0 Bill Lutz 6.99@203 in 3500# Quote Link to comment Share on other sites More sharing options...
enolakardia Posted February 27, 2007 Share Posted February 27, 2007 Here is a good site, they build a couple different setups with a stroker kit and dyno all of them. I think the biggest benifit of the stroker motor is not so much the HP gain, more so, it's the torque curve. Check out the Dyno sheets from the build up these guys did. Also, Grumpy, you are the man, I've learned so much from the postings you've done..... Thanks!!! http://www.hotrod.com/techarticles/383ci_chevy_small_block_build/ Quote Link to comment Share on other sites More sharing options...
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