306 or 347?
 

I am planning on building a motor for the summer and i am looking for some suggestions. I know a 347 is capable of making more power however i know of some people running 11.6 with a 306 and thats with a stock stall converter. Money could be an issue but what should i build? I have a set of AFR 185's on the way and i will be purchasing a Vic Jr. intake. Should i just by a set of good pistons and pump up the compression on a 306 or i was looking at a kit from jegs. It comes balanced with a balancer and flywheel but has hypereutectic pistons for $1093. I want to make about 450-475 hp will that kit handle it? I will probably be going with a stage 3 trickflow cam for now until i can save for an ED Curtis. Any suggestions would be great. thanks... sorry so long

Re: 306 or 347?
 

NEITHER! Build a 331! Best of both worlds. 347's have a horrible rod ratio, and supposedly won't last long. A 331 has a great rod ratio, and is obviously more cubes than a stock crank. We have an N/A 333 (A 331 that's 4.040" bore instead of 4.030") that runs 11.70's all day long. Good set of Canfield's, victor Jr, Cam Motion custom cam, and an old school toploader 4 speed. Can't beat it for the price man! Build your "recipe", then call Cam Motion. They'll build you a custom cam that'll light you up! Think about it, a 333 cid motor making over 500 ponies? Waaaay cool, man. Way cool! :D

Re: 306 or 347?
 

No replacement for displacement. Speed costs money. How fast you want to go depends on how deep your pockets are period!!! No way around that. As far as E.T. and horsepower is concerned, its about overall combination. Like Jester recommended, go with that combination. Or go with some other one that works. Best way to find out, the race track. You have to educate yourself for whats best for you. But cubic inches cant be replaced. Sure, someone can put a blower, nitrous or turbo on a smaller cubic inch motor and make as much or more power, but cubic inches will have more potential for power! And cubic inches cost money.

Re: 306 or 347?
 

Thanks for the respnses guys!.. Another question... do you still have to get the bottom of the piston walls machined for the 331 crank so the rod bolts clear? Thanks

Re: 306 or 347?
 

Yeppers, but not nearly as much as the 347 does, for obvious reasons. A main girdle won't be a bad idea either. Like Tarmon8r was saying, all depends on what you want to get out of your engine and car.

Let us know!

Re: 306 or 347?
 

Well i am hoping to run low to mid 11's N/A. Would you recommend dealing with DSS for the 331 stroker kit? I am from Canada but i find that it is still cheaper to go across the border to buy and pay for shipping. Jester, what do you think of the stage 3 trickflow cam? This car is going to be street/strip so i am hoping on getting 450 or more HP!

Re: 306 or 347?
 

I've never dealt with that particular cam, but I've heard good things about it. Call them (330-630-1555) and make sure all your parts are gonna work with it. That's an awful lot of duration for a street car. Not gonna be a daily driver for sure. And with .595" lift, you'll have to make sure your pistons are going to clear the valves. Remember that an engine is a SYSTEM and to get peak horsepower, all your pieces and parts have to play nice together. A big ol' cam won't do you any good if you can't utilize it. Not trying to talk you out of that cam, but there might be a better one suited for what you're trying to build.

Re: 306 or 347?
 

Thanks for the response. The car will not be a daily driver just cruise in it on nice days and cruise nights, car shows etc.. Just want something to run at the track when we all go and run 11's.. then possibly race on the streets.. for fun

Is DSS a good choice to deal with for stroker kits?

Re: 306 or 347?
 

The 347 kits aren't bad at all. The rod-ratio on a 347 is better than a 350 Chevy. It was just the very early 347 kits that had oiling problems

Re: 306 or 347?
 

We want it to run better than a dumb ole Shivvy! LOL But you're absolutely right! It's just my personal opinion that hanging that big of an arm in that little block is taking a big chance. Same reason I decided NOT to build a 427 for my car. Just what's running through MY head, nothing more.

Yes, DSS, CHP, Bennett (ours is a CHP kit, 2nd car is a bit more exotic, no kits here!) are great sources for stroker parts. Have them balance the rotating assembly for ya, it's only a hundred bucks or so if you have them do their own parts. Local machine shops whack ya pretty hard if you bring your DSS crank to them to balance.

Coast High Performance Bennett Racing DSS Racing

Re: 306 or 347?
 

Yup definitely want to run better than chevy's!! Thank you for your opinions guys. I have not decided what i am going to build however it will either be a 331 or a 347. I will post it when i decide. Thanks once again!! Whay hp are people getting with their 331 vs 347? What are they running in the 1/4?

My combo will be: AFR 185's w/ 58cc, Vic Jr. intake, 750cfm, stroker kit w/ 10.9:1, and probably trickflow stage 3 cam(for now until i can save for custom cam), C4 w/ 3500 stall, 4.10's
Is there anyone w/ similiar combo out there? Let me know
If there is any suggestions for off the shelf cams post them please!
Thanks

Re: 306 or 347?
 

I just noticed your wanting to make 450-475 N/A hp with this motor. That's gonna be hard to do, about the only way to do it would be to throw in a big cam, some AFR 205's or simmilar head and spin it to the moon.

Re: 306 or 347?
 

Well i am planning on going with the satge 3 cam which specs are .574/.595 with a 298/310 duration. I know a guy who will be running in the low 11's with AFR 185's, Vic Jr. and a cam that specs out around .580 ( don't know exactly but its close to that) His engine is just a 306 and i figure he must be pushing about 425 hp. So i think it is realistic to run 450-475 with a stroker motor. I mean you never know.. but the assumption seems about right.

Re: 306 or 347?
 

It only takes about 340 RWHP to run 11's

If you want 475HP I would go with a 351 for sure and stroke it to a 393.

My brother in laws 393 made over 400HP and torque to the wheels with box stock edelbrock victor junior heads, custom cam and a trick flow intake.

Re: 306 or 347?
 

Sorry for the confusion.. i meant 425 at the flywheel.. well i can't afford to do the swap .. so the 393 is out of the question.. but i do know they make huge torque and horsepower.. friend of mine has one and ran 10.80 last year.. but i know it will go faster.. Thanks for your opinion

Re: 306 or 347?
 

I don't think 475 flywheel HP is unreachable at all. That 333 we built is putting out over 500 at the flywheel (calculated on weight & ET) Noone around here has a dyno. It has a GOOD set of Canfields, vic Jr. intake, 750 Holley, and a custom cam from Cam Motion. Hooker Super Comp headers, X pipe etc etc. It'll run 11.60's N/A all damn day. That and it sounds really pissed off!

Speaking of Cam Motion, my new cam showed up yesterday! Woo Hoo! What's the little wheels on the lifters for? ;) ;) hehehehehehe

Re: 306 or 347?
 

Hey Jester, i will be running a similiar combo.. but different heads (AFR 185,s) What are the specs of your cam... i am just wondering if you could let me know.. still waiting to get email back from cam motion..

Re: 306 or 347?
 

I cant take credit for this quote: The best rod ratio is 8 to 1. 8 rods and 1 crank.

Andy

Re: 306 or 347?
 

I like that quote Andy. LMAO!

Re: 306 or 347?
 

Which specs? The 333 or the 408? Got 2 cars (building #3 as we speak) Car#1 the 333. is "mild" and I'd have to look up the specs for ya, don't remember them off the top of my head. She's running a sold cam though, for sure. AFR 185's are close, that motor has Canfield with 200cc intake runners. Should be pretty good comparison though. I'll dig up the cam specs on that one.

Car #2, 410" Windsor engine, 1-off Canfield's (I know the owner! :D ) Cam Motion solid roller cam, .647/.622 lift 252/259 duration, and alllllllll the goodies below that. Still in progress.

Car #3, 393" Windsor "budget stroker". Meaning custom crank, stock 351 rods, stock 302 forged pistons. This is the "How fast can ya go on stock parts?" car. Should be lots of fun though!