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307 chevy question


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Has anyone on here ever used a 307 far a performance engine? I have a 307 and a 305 which is in my car now, but the 307 is out of a 69 camaro and is rated at 200hp and 300tourqe, the 305 is only about 140hp and 240 tourqe. I would like to get about 250hp out of the 307 whith basic bolt ons. I also heard that 350 heads will not work on a 307, i guess cause the valves are bigger and the cylender is smaller. Any help would be great. thanks

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The 307 has the bore of a 283 and stroke of the 327.

 

You can easily get the horsepower figure that you are shooting for with bolt ons.

 

Go with a good dual plane intake and a 600cfm carb - or even a good quadrajet.

 

I have always liked the idea of turboing a 302 Chevy engine, for gas mileage and rod/stroke ratio reasons.

 

Definitely don't need all the low endf torque that a 350-400 small block produces, but a lot of top end!

 

The 307 was the economy V8 that Chevy used when they wnet to the 350 small block for performance, it had good torque for its' size.

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Guest traub83

I have a set of 882 heads that have about the same miles on them but I did a mild port and polish job on them im looking to unload to fund my turbo project!!

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Guest traub83

Yah bro, I just took my heads apart then got the drimmel out and bought some porting ohh man I went blank but the blueprints or whatnot on them lol and did mine according to the prints turned out really nice!! I never have ran them since I put them backtogether and porting but I bet would flow nicely!! As for bolting on your 307 yes they will bolt right on no problems whatsoever with it.. Prob flow quite well what size valves are in your 882's?? Im wanting to say all were 1.94/1.60 but I could be wrong and I think thats what mine are. If that is what they are I wouldnt change the valve size at all for a 307. And if ya use a decent camshaft I think your 200-250hp goal will be easily done!! In fact u may go over your target goal but im sure you wont complain about that huh!! :-) good luck bro ask away if ya run into problems or whatnot and I may be able to help ya with the porting job on them if ya need help but then again im sure there are people on here that would blow me away in porting and such as I am still an novice when it comes to that!!!

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thanks for the info. Im pretty sure all 882's have 1.94 inch intake valves and 1.50 exhaust. Hopefully i can make the extra 50 horse power relatively easy. I plan on using the 882 heads with mild porting, maybe a mild cam if i have the money, a GM four barrel manifold off my current 305 a holley 600 spread bore, and im gonna try my hardest to fit some long tube headers in there.

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they should work then. 305 has a bore of 3.75 and a 307 has a bore of 3.87. plus the engine i am using is bored 30 over so it is really only one thousandth smaller than a 350 bore, i cant imagine a measly thousandth of an inch would render the 882's unusable.

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Guest traub83

see there ya go. and on a 350 stock bore you can run 2.08/1.65" valves without a problem so i dont see why 1.94"/1.50" valves would be a problem on a hair smaller size cylinder??

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I once had a 307 with 882 heads with 1.94/1.50 valves, altough it was stock it was a fairly good motor. A friend of mine had a 76' Camaro with 307, th350 trans, 10 inch 3500 stall converter. The 307 had a comp cams 292H magnum cam, 10 to 1 flat top pistons, a torker intake, (I think), 750 dp holley, stock HEI distributor, stock camel-hump 2.02 heads. The car had 4.56 gears, it ran mid to low 13's. In my opinion the 307 is a much better motor than a 305. If this is what you have, and you want to stay low budget, I say go for it! If I were you, I would build the 307 with your 882 heads with bowl porting and gasket matching, maybe an edelbrock rpm air-gap intake, 650 dp carb, 1 5/8 headers, comp cams XE268 cam, HEI distributor. Anyway, good luck in your 307 quest.

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Guest traub83
what kind of z do you have traub?

 

Alf I actually have 3 Z's

 

one is going to be our (meaning my friends and I full time race car)

its a 78 280z and we have a 350 with a 144 prostreet supercharger on it, we pull 10.5's in it currently, however we dont have a cage in it so untill we get it up to spec we cant run it again. We are working on it however...

 

The other is a 72 240Z I am working on right now and hope to have it done march/april of next year. I am building a forged twin turbo 350 for it the one I am posting left and right about.. This is my first turbo motor I have ever done besides motors that were turbo factory so Im still real fresh with boost from a turbo...

 

My 3rd Z is a junker its a 77 280Z Its rust free however just in bad shape otherwise.. Maybe one day I will do something fun with it and give it to my future son/daughter or something but till then in the storage shed it stays..

 

Now My brother just bought a 280Z For the life of me tho I cannot think of its year. Its pretty sharp and runs good with the L28 motor in it. However He is buggin me left and right to dump the l28 for him and drop in his 360 mopar in it... I am kinda tryin to keep him from doing it as his Z he picked up is darn near cherry and orginal and has a very fresh L28 in it.. car has 100+K miles on it but by lookin ya would never know and the motor was rebuilt about 15K miles ago and its very fresh and starts on a dime and runs very hard for bein stock or so he says..(I have my suspesions that the previous owner souped it up a lil as it idles rougher than normal, and the powerband is a lil high witch makes me think aftermarket cams, also it has a K&N intake on it that had a drill hole in it the exact size of a nitrous fogger) And it is clean... I donno where my bro found it at but he does have one nice Z and I am tryin to talk to him into keeping the L28 motor.. And if he wants more power just to turbo it with 6-7 pounds of boost but hes very hooked on droppin his 360 into it... And I prob will end up doing it, cause if not he will start wrenching it and jerry riggin in his 360 and mess up the car and I can't have that so tune in to me soon cause there may be a sweet l28 motor for sale here soon....

 

But those are the cars I have and car that im close too.... Maybe one day I will get another Z or build my 77 to be a roadracer and drop a Ka24de motor in it.. ya ya ya I know why not just go SR20 right?? well my answer is this the KA24's are everywhere cheap!!! and they are good motors and have lots of potiential just people like the sr20's cause there turbo stock which makes since however. U do some mods to a KA24 and you have a warrior with more cubes and add boost and you could have a 500hp monster. Ive seen a few and personally id pick a KA motor over a SR motor personally but thats just me.. But im like anyone else id take an RB motor over eather lol...

 

Hope I answered your Q's bro... Good luck to ya and just ask away if ya need help.. cause there are guys way more knowledgeable than I on Z's and motors for that fact however if i can help I will otherwise what good is a fourm huh???

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If anyone has a desktop dyno could you please enter these specs in and see what kind of power you come up with thanks. 307 ci 3.9 inch bore, 3.25 inch stroke, 9 to 1 compresion, 1.94/1.50 inch valves, .454 in lift, 205 duration at .050, GM egr four barrel intake manifold, holley 600cfm spread bore vacuum secondary 4 barrel, chevy points distributor, Z/28 windage tray, 1 5/8 long tube headers(this is with no fuel pump or fan)sorry i am not sure on the piston design of the 307, the heads are 76cc chambers

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