Hey guys... I'm putting together a grocery list to see if the current financial situation will allow me to build another motor for the '55, and I'm not exactly sure where to go with it! The '55 has been a drag car since the 60's, and has a '57 Poncho rear with a 5.13 posi. Just for the cool/nostalgia/history factor, I DON'T want to change that. She's running 28" tall tires right now, and it looks about perfect, so I'd like to stay close to that; plus, an inch or 2 in diameter doesn't make THAT big of a difference with the gearing. I don't like to take the motor that's currently in it over about 6000rpm or so, which comes up REAL FAST with that gear. To run trap speeds in the mid 120's (The current motor should run low 11's with proper gearing), I need something that will safely spin to 7500 or so. (The guy we bought it from was shifting at 9200 with a 327! ) I know that those kind of revs are hell on valve springs, and that I'll need a strong/light valve train, good heads, etc... I can handle all of that. I'm just unsure of what size motor to actually build! Some of the combos I could build with blocks/cranks that I have: 1. 301/302 (283 crank/4" block) 2. 327 based motor 3. 350 based motor 4. short stroke 350 (327 crank/400 block - IF main bearing spacers are available for that. I also have a large journal 327 crank, but it's cast; I don't know if I'd trust it) 5. 377 (350 crank/400 block) These things are a constant for any of them: light pistons, strong rods/bolts, 4 bolt block (except the 400's; I'd likely stay with a 2 bolt block and possibly run a girdle) with ARP main studs, balanced assembly, good SFI damper... I CAN'T afford aftermarket cranks or splayed cap conversions at this time! What should I do? What would you do? Any ideas/concerns that I didn't think of? Am I an idiot for opting to build a new motor vs. change gears? Am I an idiot for wanting to go fast on a budget? Ok, let's have it guys! Thanks! Steve
Steve, Every one wants something for nothing, free horsepower, money for nothing and chicks for free. Or something like that.
I like you're first choice. A cool little 301, 4" bore and 3" stroke. If built right it should handle those rpms easily. Seems like you got the right set of rear gears to have a high rpm motor. I guess it depends on what you have kicking around but I know I have two 350 4 bolt main blocks sitting around so I'm gonna find a 283 crank and buy some oversized bearing and throw it all together. And then get a high rpm intake, tunnel ram or cross ram sounds good
Here's a little known fact that may help you with your quest for low budgetness. the 4.3L L99 "Baby LT1" from the '94-96 B-bodys uses a 3" stroke, and will easily handle 7500 RPM. If you get a later (non-LT1) 350 block with a 1 piece RMS, you can swap it in and get your 302. The LT1 rods have also been sucessfully used over 7500 RPM, and are as good as, or better than the GM "Pink" rods. Another advatnage of the later block is that it's already a roller setup, so you can use factory lifters with a monster roller cam.
How fast do you havta go? Those 302's would scream, and new spring/cam technology could help them live longer. But the bigger mills might move you faster Go parts hunting -- you'll find something that will jump out at you as the way to go.
Another thing you could concider is a T56 6 speed trans from a late F-body. The extra gears would work well with the rear gears. Not all that traditional, but you can't see it unless you are looking for it anyway. Just a thought...
What are you doing to the cranks to keep them alive at that RPM? I have not had that kind of success,, in fact failure was usually a sure bet if used above 6800 in a street strip enviroment....curious as to what you found to make them stay together what rod bolts are you using in the LT1 rods? Fred
A stock sbc can and will take high rpm if they are complemented with good parts such as arp rod bolts and good valvesprings as those are usually the deciding factors in keeping a motor together. The old small journal forged rods have been seeing those rpms since those motors came out. The good thing about going small displacement is that you don't need the monster airflow of a big motor so you can get away with a smaller lift cam, (.500 lift range) letting you have a little more room if you let the motor wind up a little too far for your springs. Make sure you put the motor together with a good quality cam with matched springs and valves, good pushrods and guideplates.
short stroke LOTS of valva spring is the ticket ci.doesnt matter just short stroke. spend the money on rods thought, and a roller cam helps loads.
Ok I gotta chime in here, and I'm SOOO over it when it comes to drag racing. However, why the fuck not change the gear and build the BIGGEST ci motor you can? Talk about saving $$$! Not to mention the future $$$ in broken parts and worn out valve springs. My mind says get gobs of TQ and carry the front runners in a long and graceful fashion for like 60' plus and go well into the 10s. So many guys are converting to BBCs that some good race stuff for SBCs ought to be around. Not long ago a racin bro got a JUMBO deal on a Kryptonite crank for his 377 combo. He banged gears at like 8200 in a Vega with (again used) a Buick fabricated tunnel ram and symetrical port heads designed for class racing. That car was in the 8s at all times and granted a dedicated race-only car. Following that practice though could net you some great results. I guess it matters more of what you wanna say vs how it runs. Maybe it's more fun to show a time slip?
Hey Man... If you're determined to spin high rpm (and it sounds like you are), do us a favor and get a set of these: http://www.cranecams.com/index.php?show=browseParts&lvl=4&prt=2148 They'll help stabilize your valvetrain enough to live up there. If you want more specific help, PM me with what you've got and/or what you want to use. I'll do some homework for ya and come up with a game plan that'll make the best of it and help get you where you want to go. It's not what I'd do, but I ain't the one doing it. You know I'll do anything I can to help you out and steer you in the right direction. ~Scotch~
I know what you're saying Highlander, but I already have a "go fast" car. This is the "look cool as fuck and go pretty fast" car. Like I said, I kinda like the idea of leaving the car as it was originally built; if I change too much stuff, I'm afraid it'll lose a lot of it's soul. For me, when wrenching/driving/looking at it, the car's history is what makes it seem so much cooler than any of the other 55's out there driving around... It's the real deal, ya know?
There goes the budget... a good idea, but not low buck. I don't know if its possible to build a high revving engine, that will survive on a low budget. You could look to the NASCAR market... there is that place in NC that sells used NASCAR stuff. They rev the piss out of em for hours at a time. I can think of no more grueling of a test than Atlanta where they turn 9500-9800 rpms for 4-5 hours... but you are getting into exotic SB2 and 18* headed stuff... Since I don't really know about the high RPM stuff, all I can suggest is to get the gameplan... and stick with it. Think before you buy. ...and buy from me. Its gonna be cool!
This engine came out of a Camaro that nobody could compete with. It's a 350 block, 0010, with a 302 forged crank. It was shifted in the high 8's. Stayed together for 3 years doing that. It's sitting in the back of my '34 pickup waiting for me to get the guts to put it in something. I had a '68 Z-28 in 1968 and I remember what the factory 302 would do. This is way beyond that but the sound of a wound up 302 is really addictive. I'd vote for a 302.
For those RPM's I would stay away from a factory 400 block. They tend to split the deck or crack the mains when really stepped on hard. I like reliability and its hard to get with things like stock rods and 400 blocks. For reliability I would either go for used NASCAR stuff since its the best of the best, or brand new good aftermarket for the rotating assembly. You can buy NASCAR shortblocks for around $4000 if you look around and you end up with a block that will usually have parts from top notch manufacturers like Bowtie, Kyptonite, LA Enterprises, Carillo, Oliver, JE, Mahle, etc. They usually have flattop pistons in them also. Only issiue is they are dry sump and need to be converted to wet (not a big deal). If thats not your thing... I would find a good 010 4 bolt block for its 4" bore and since they are a good stable block and easy to get. Bore it as little as possible. Do a short fill of Hard Blok. I would get a rotating assembly kit from someone like SCAT where you can get the crank, rods, and pistons all at once. To keep costs down I would get a stock 3.48" stroke. They are around 1200-1500 and other than machine work, your shortblock is done. Make sure your oiling system is up to snuff. You will need big heads to make power at those RPM;s. A good inexpensive aluminum head is the DART Pro 1's 215 cc intake port. Drop a little coin getting them mildly ported and they will outflow AFR's and Brodix heads and still be several hundred cheaper. A solid roller cam is a nice to have for those RPM but not needed. A stout race flat tappet will do it. Tight lobe seperation and a duration at 50 of around 260 degrees will do it. Use a circle track lobe since they are softer and easier on the valvetrain since you want to drive it on the street. Run 7/16" studs and 1.5 ratio rockers and add a stud girdle. Keep everything light and you probally will not need a rev kit. A tunnel ram would be good for a motor like this or a large single plane with lots of plenum volume. Lots of carb would be good also. 7500rpm really isn't too bad since a lot of circle track motors spin this. I quickly did a DD 350 with 11:1 compression and the Pro1's listed above with a tunnel ram, 1000cfm worth of carb, large tube headers, and a mild 258 duration lunati flat tappend (only 512 lift) gave over 550hp at its 7500rpm power peak.
Trust me when I tell ya, I do understand. It's nice to have an "internal combustion die grinder" under the hood. Make it sing hi pitched tunes...I get it. Just addin the devils advocate view. What's your "go fast car"? I had one but like I said I'm over it. Too much $$$, time I just don't have, energy I'd rather point elsewhere, and friends doin it still that can always use help. I guess if I can't have a 417 Donovan in front of me in a FED on nitro I'm just gonna have to stay "over it". Here's my last effort...
If this were my "look cool car", I'd just change the gear. Still available from Mark Williams last time I looked. Would be lots cheaper and easier to do. I love high winding small blocks but they seem to leave lots of oil on the pavement from time to time.
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