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Pure American Muscle
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Discussion Starter #1 (Edited)
307 Mud boggin cam

Hi everyone,
I'm building a 307 for my friends jeep. I have never messed around with a 307 cam before and im having a hard time picking out one that will work well with the engine. The jeep has big 33 inch mud tires and 4WD and a MAN. trans so I want to get him a cam that has as much bottom end as I can so that the engine will really pull down low and im not so worried about the top end it only has to get up to highway speeds. I hate asking these questions because I know it is something that no one can pin point but I just wanted to see if anyone can give me a good idea
Thanks everyone! :pain:
 

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Could you tell us a bit more about this engine??? Heads, bored, asperation, ect.?? From there I can hand down a bit more info. I have a 2 of these in 2 of my 5 jeeps.
 

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you should consider using a 350 crank instead of a 327 crank.that way you end up with a stroker motor.the 307 has a bigger bore than the 305 but uses the smaller crank.if you are looking for grunt and you have to use a 307,you could't do any better than to make it a stroker along with almost any bottom end cam.but why a 307?
 

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Pure American Muscle
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Discussion Starter #4
Sure can... The engine is will stay mostly stock.
1.The block #3970024 2 bolt
2.Heads are #3986339 with 74 CC chambers stock valve size.
3.No bore just org. block
4. Pistons are 8.5:1 flat top
5. Has an Edelbrock Performer intake
6. Holley 600 CFM carb.
7. Headers

The rest of the engine is staying stock. We just want it to pull real good and have lots of low end for off roading fun:evil:

Thanks again and sorry for the lack of info I should know better by now!:rolleyes:

Also we are useing the 307 because I have the block here from my engine pull and it's just sitting around. If you say my friends jeep engine you would understand why we want to just use the 307. And I also heard that putting in the 350 crank really dose'nt do alot for the engine.:smash:
 

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Best bet don't guess.. pick up the phone and call comp cams.. 1 800 999 0853 its a free call... they will ask you questions... they will give you a part number... take the part number and call summit or jegs or go to your local speed shop and get the cam... too easy huh?

Two reasons why I say comp cams, more engine vacuum and slightly more torque than simillar grinds.

ONe question, how is it more cubes wouldn't improve low end torque?


Nice chevelle..looks good.


good luck
 

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Pure American Muscle
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Discussion Starter #6
Yea I will do that too I wanted to see what or how other people had in their engines and how they worked.

For the 350 thing from what I have heard that even though the 350 crank up's the cubes the bore size of the 307 is still to small to really get much of a worth while increase.

And thanks gotta love the Chevelle

:thumbup:
 

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Your right the 3.8**" bore probably wouldn't be as optimal for gains as the 350's bore, but seeing how cheap 350 cranks are, it couldn't hurt IMO.


I have heard many many positive responses from those that use the extreme energy grinds from comp cams, especially the positive increase in torque production, in low compression engines.


Good luck
 

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Pure American Muscle
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Discussion Starter #8
Yea I have heard good things too I will call comp and see what they have to say. It could be worth a try putting in the 350 crank I will have one once I take my engine apart but that won't be till later this winter. Also I thought there was something to do with the journals on the cranks that were diffrent and wouldn't let the 350 crank go in the 307 block but I could be wrong:smash: lol If possible though I too say it wouldn't hurt. Thanks again for your help everyone.
 

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If it were mine, and being it`s for a 4X4 I would first get a set of a 305 heads, the 416 castings, they have the 160cc runners and slightly bigger valves, this would bring your compression ratio into the high 9:1 area due to the smaller chambers and the slightly bigger valve would help with breathing. then I would use one of comp cams 4X4 torque grinds, I would also use a Rochester Quadrajet carb. The 307 was made to be a torque engine from the get go, as for using a 350 crank in it, it would give it a torque increase, but the cost of having custom pistons made wouldn`t be worth it. by using the pieces I mentioned with a X over pipe would give it real good low end torque and throttle response.
 

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Pure American Muscle
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Discussion Starter #10
Wait I correct myself that was the 305 that had diffrent journal size the 307 is the same. I could put in the 350 crank and make a 328 stroker or puch it 30 over for a 333 engine. A gain of that cube will do something lol.
 

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Pure American Muscle
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Discussion Starter #11
from what I can find on those heads they have a 58CC chamber? if so that from a number of diffrent compression cal. pushes compression up to 9.5 is this correct? I know many things effect compression and those are just cal. ones but if that is correct would that be too high for this engine? or is it completely safe because if it is then that would be great! lol
 

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first off the 307 is a great motor, I hope it runs well for you. IN a truck I would definately use an RV cam, and maybe even a roller. Heck, you always have that cam from now on, because they don't wear!! SO if he wants to go to a 400 later on, he already has his cam. Same goes for rockers.

I used a crane roller a while back, worked great-

K
 

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you guys need to get out a little more or do a little more reading or something.they're putting 400 cranks in 350's,305's,265 ll gen..and you don't think that a350 crank would help the bottom end or any other part of it.i was at jegs 2 yrs. ago in the first part of summer and they had a dyno you could put your car on for free if you got there early enough the nite before and waited in line.there was i guy had a 400 crank in a 305 in a 78 nova.it didn't make much power but what it did make was from the bottom to the top.the numbers barely changed.a stroker is astroker is astroker.i didn't say the 307 would make 400 h.p.,but you said you were looking for grunt.a 350 crank is as cheap as a 307 and that's some of the best grunt you could get.
 

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GoneNova/406 said:
you guys need to get out a little more or do a little more reading or something.they're putting 400 cranks in 350's,305's,265 ll gen..and you don't think that a350 crank would help the bottom end or any other part of it.i was at jegs 2 yrs. ago in the first part of summer and they had a dyno you could put your car on for free if you got there early enough the nite before and waited in line.there was i guy had a 400 crank in a 305 in a 78 nova.it didn't make much power but what it did make was from the bottom to the top.the numbers barely changed.a stroker is astroker is astroker.i didn't say the 307 would make 400 h.p.,but you said you were looking for grunt.a 350 crank is as cheap as a 307 and that's some of the best grunt you could get.


Who said it wouldn't help low end torque?:confused:






Strikingthematch

The 305 heads would increase your compression ratio and work well for what your after, and this is also a good reason to call the cam company. The cam you use is dependant on many thing and compression ratio is one of them. Some cams are designed to build more cylinder pressure to compensate for low compression ratios and vice versa so you wanna know your ratio before you have comp help you select the cam. Good luck
 

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Pure American Muscle
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Discussion Starter #15
Very good point 357Ford I know that from working with 350's but with the 307 it was a little diffrent ball park something that I wanted to make sure of before I did the wrong thing for my friend.


GoneNova/406
We all agreed that it WOULD help the bottom end but not enough the make the having custom pistons made for it. I contacted a few piston companies and it is a custom job. For the amount you would gain vs. dollar amount it just wouldn't be worth it unless you had unlimited change in your pocket which my friend does not.
As I had said the small bore size of the 307 helps to kill the any power gains. HOWEVER if I would find those pistons to put in to the engine I would do it in a second do it. Thanks everyone!
 

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307 may have a small bore, but it will respond to upgrades better than any crap 305! I wish they had built more 307's, put them in the 80's cameros and such instead of the 305.

K
 

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Pure American Muscle
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Discussion Starter #17
I second that to no end!
Im looking for parts for the 307 and there are a few places that sell stock replacment parts but if you want and type of higer pro. stuff forget your payin an arm and a leg!
I will agree that the bore size is not to bad esp. if you increase the stroke it would help but it still factors into making it harder to produce good numbers. How much I would gain I really don't know but I sure would like to do it! lol

I hope that by putting on the other heads and a new cam we should be able to kick up that bottom end pretty good. Enough that he will be happy which im sure he will be.

I'll let you guys know what I find out about the cam and heads.
 

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What's a 307? It's a large journal 283 with a 327 crank. Now that's got to be good base for your project. I'd go for the 305, 58cc chamber heads as well, or even the power pack heads as the smaller port sizes would improve low air speed flow and boost turbulence by a huge margin. That means torque. I'd also use rams horns manifolds instead of spending money on headers which may hurt low speed pick up. The base cams in those babies are built for emissions, so any sensible RV style of cam is going be noticeable instantly.
 

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Pure American Muscle
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Discussion Starter #19
I contacted ross pistons and a custom set for the 350 crank would cost $689 Iam still waiting for some emails back from other companies. I believe it's pretty much a go for the smaller heads as this seems the best way it up the TQ.
 

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Why not just hang the stock 307 pistons on a set of stock 400 rods? A .020" cut off the deck( that the soft block 307 probably needs) and a 1094 Fel-Pro gasket should have you in the .040" quench range......Dan
 
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