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I am buying a 388 sb to put in a 67 chevelle an it is about a 680hp motor an it is 12 to 1 compression that is to much for pump gas , can I change cams and detune engine with smaller cam an put a thicker head gasket on it an get compression down enough to run on street with pump gas.
................nope
Assuming aluminum heads you'll need to get your compression ratio down to about 10.5 max, and you'll still be looking at 91/92 octane fuel.
.....nope ... cam may not play good and then theres intake . better start with clean sheet so you pick up a engine thats makes 680 HP ? was that the selling point .when i build a engine like this ring end gap not the same as many other things better to start with a clean sheetQuote:
Originally Posted by rspears
Pat, I wasn't commenting on the overall build, simply pointing out that his compression ratio is at least a point & 1/2 too high for pump gas, and he's not going to get there with thicker gaskets, which is never the answer to dropping compression.Quote:
Originally Posted by pat mccarthy
no kidding go back to my first post ? nope... he came on here and i would go out on a limb????? say that he knew that the way the engine is now will not run on 93 so nope was posted on the way he was going after it . lower cr pistons cc dish or big cc chamber heads is the rigth way going after it may be better to sell the 680hp sbc and build a more friendly street engine bulidQuote:
Originally Posted by rspears
Hey Ken, saw this is your first post and forgot to welcome you to CHR! Hope that you don't let the third person replies put you off, and that you'll stick around and keep everyone here in the loop on what you're doing with the Chevelle. There is a wealth of good information you can glean if you stick with it and keep focused on questions you may have.Quote:
Originally Posted by Ken1960
Ken, sure would be nice to see some specs on what's actually inside the engine in order for folks to make some suggestions on dropping the compression to a streetable number!!!!!
Oh yeah, welcome to CHR!!!!
Don't worry guys---it probably is only about 400 hp to begin with and will run fine as is------------
He suppose to send me build sheet I don't no all of the particulars about yet I do no the machine shop that built it an he is looking for build sheet also ,he stays very busy , I know he said it was a 10 second truck s-10 , I know the builder an he is good or I would not be interested and it is more than 400 hp , it's not my 1st rodeo
Welcome to the site Ken---hope you can stand a little bit of stuff--what kind of supercharger did you say was on that 388?
Welcome aboard Ken! Good to see you here.. you've made quite an entrance!:eek::LOL::LOL:
We're not a bad group.. like any family, we get a bit "dysfunctional" sometimes.. but don't hold it against us! We only want the best for you and your ride..:)
Dropping the static compression ratio with thicker gaskets will increase the squish dimension and may contribute to detonation more than if you kept the tight squish and higher static compression ratio. So says John Erb, chief engineer for Keith Black Pistons.
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I might need to move on to a different motor, maybe a Newer style engine I hear they got a strong bottom end .
Are you referring to an LS base platform?
Yes I would like to have at least 475 to 500 hp an have enough vacuum to run air
Looking at some of the buildups the magazines have done, and the crate engines available in the LS based engines that shouldn't be hard to do!!!! We have a local salvage yard with their own shop that sells LS engine and trans combos complete with wiring harnesses, I'm sure there's any number of shops doing the same thing across the country.... Good horsepower and decent economy, not a bad set up IMO!!!!! Might want to check into what's available in your area before spending a bunch of money!
vacume to run air??????????
If you are going to look at the late model LS from salvage yards as a transplant package---engine, trans, ecm wiring harness--you need to do quite a bit of research and learn exactly what the pluses and minuses are of the different packages--in addition to the engine/trans you will need a complete exhaust and fuel system plus most likely a new radiator/cooling system--------also your a/c will need to be upgraded to 134.
While you are researching the packages, decide what your budget will be and start centering your sights on the level that your willing to spend------and then stay focused on your target instead of jumping on some lessor level deal that was too good to pass up----------
It sounds to me like you have a lot to consider. First would be budget, and intentional use of the car. These swaps are going to cost you plenty. The engine, trans cost is only the beginning. At at least 500 hp in your chevelle, how are you planning to get it to handle, hookup etc.? Like I think it was Jerry who mentioned all these things in a earlier post. You have to decide if you want a good streetable car or a drag car. You are probably looking at 30-40 grand if you do it all your self. Then comes the car itself. I know it sounds like alot but if you keep records you will be surprised at what it will end up. You can build a 383 stroker, 10.5-1 compression,decent heads, good quality parts,built by someone who knows what he is doing, That is streetable, dependable, and still be a handfull of fun for about 25% of what all these major mods will cost. JMO
Ken--------lots going on here----
If the pistons aren't the ultra liteweight hollow dome type---the domes can probably be cut down to lower compression to an streetable combo for available fuel-if you live in an area near a race track some stations might have a race fuel available at a decent cost level (blend with pump gas)
I just did carb build tune on a 434 sbc with Holley 80511 carb that did 450hp 468 tq on pump (93) gas with limited timing----early Camaro, fixed the drivability issues---now only drawback is you can't floor it while in second without spinning????????????oh, well, try 3rd------was a fun test ride
I can't put 20 to 30 thousand in it, I'm looking , the 388 I 1st looked at I thought maybe I could tame it dn without spending a lot of money . The guy that built it is a good engine man , and today a guy told me about a 604 sb that he bought for a late model crate engine he ran it 3 or 4 times an is quitting racing he said it was about 400 hp , but I don't no nothing about that kind of motor. I just want something to pull hard to play with these boys up here with them big blocks around town. They giving me a hard time
then why not a bbc?Quote:
Originally Posted by Ken1960
Good advice. You could get the best of two worlds and low maintenance. And easy to swap. Those thousands I was talking about on the other post was not just for the engine and trans, but for matching the rest of the car to the swap. It comes a couple of thousand at a time. A BBC would be the least expensive way to go and still be happy in the long run.
How much more does a bb weight compared to a sb There is a crate motor that is a 427 bb with 450 hp out there does anyone know if they are ok
well why stop at 427? the 496 and 489 are what i build the most of for street use and cost would be the same of a 427 both use the same block 9.800 and 4.250 bore plus the added bore size 4.280 or 4.310 using a 4.250 crank gives you a 489 or496 if a alum head bbc 570lbsQuote:
Originally Posted by Ken1960
That not bad at all close to a sb. Finding one will be the problem , would like to have a 4 bolt. I need to get some direction I'm going pretty soon would like to have done a. s p
no they are not i have many cores that will make a nice 496 you do not need a four bolt its a bbc not small block a two bolt bbc will take more power then you think before caps walkQuote:
Originally Posted by Ken1960
How much would it cost to build a good strong engine with aluminum heads run on pump gas. My bad
Quote:
Originally Posted by Ken1960
You might want to PM Pat
I tried to pm you an I guess didn't do it rightQuote:
Originally Posted by pat mccarthy
Pat has been banned, maybe one of the other engine experts will step up to the plate and help you out.Quote:
Originally Posted by Ken1960
Yea I need a good engine man
Still haven't got a motor
Pat has the ability to contact you and you can reach out to him! Simply click on his name on the upper left of any post and send him a PM.
Or get his info and give him a call! He's already gone to bat for you, give him a chance to win you as a customer.