What should I do..keep the 306, go 357, or 408?

Pokageek

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#1

• Jan 17, 2007

• #1

I finally have the 306 running perfect and getting a oil leak fixed this weekend.

I want more low end power than I have on my heavy vert. I really don't want to spend $2300 shipped on a shortblock for a 408ci considering it will cost for lots of other ancillary stuff like HG and removal and reshoe-horning a new engine, etc..

I can get a 357 shortblock for $1200 and it would give me lots more low end and overall power. Will it be enough? I should be able to get around 425FWHP out of it.

 

1slow95

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#2

• Jan 17, 2007

• #2

If you're concerned about cost, don't go with the 408. The 357 will have almost all the same costs as the 408 except for the short block. I would go with either a 347 or a kenne bell. Either one should be cheaper than moving up to the 351 block.

Are you planning on reusing your current H/C/I?

 

Pokageek

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#3

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Yes. I will be reusing my heads at least.

 

Iggyshane

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#4

• Jan 17, 2007

• #4

I was thinking the same way mike was.. i would go with a KB it would put you around the same place as the 357 with out all the extra work switch over to the 351 block.

 

1slow95

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#5

• Jan 17, 2007

• #5

1. Those heads would be two small for a 408. They'll work and make good power, but you'll make a lot more power with larger heads.
2. The 5.0L uses smaller head bolts/studs, so you will need to have the bolt holes opened up for a 1/2" bolt/stud.

I would count on at least $2000 or more in additional parts needed to go with the 408.(headers/exhaust, dizzy, injectors, intake, oil pan, other misc. parts) I wouldn't even consider the 357 because you can reuse most of your old parts and make pretty much the same power with a 347.

Basically, if you have the cash go with the 408. If not, stick with a 302 based engine.

 

Pokageek

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#6

• Jan 17, 2007

• #6

Ok Low. Thanks for te advice man.

 

Pokageek

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Jan 18, 2007

#7

• Jan 18, 2007

• #7

Low-5.0 said:

If you're concerned about cost, don't go with the 408. The 357 will have almost all the same costs as the 408 except for the short block. I would go with either a 347 or a kenne bell. Either one should be cheaper than moving up to the 351 block.

Are you planning on reusing your current H/C/I?

Click to expand...

Only prob with kenne bell is that I am running 10:1 compression. I a mnot sure how much HP I could get out of it and whether or not dumbing the timing would make it slow in lower RPMs.

Plus a kenne bell is like 3k right?

 

1slow95

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#8

• Jan 18, 2007

• #8

Yeah a kb is kind of expensive, but they make a ton of torque. With full boost at 2000 rpms I don't think you can mess up the low end. But, with 10:1 compression I don't think I would add boost. It would be possible to make it work, but it's still not a great idea.

 

Black95GTS

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#9

• Jan 18, 2007

• #9

Pokageek said:

I finally have the 306 running perfect and getting a oil leak fixed this weekend.

I want more low end power than I have on my heavy vert. I really don't want to spend $2300 shipped on a shortblock for a 408ci considering it will cost for lots of other ancillary stuff like HG and removal and reshoe-horning a new engine, etc..

I can get a 357 shortblock for $1200 and it would give me lots more low end and overall power. Will it be enough? I should be able to get around 425FWHP out of it.

Click to expand...

I think a 347 would be ideal for you. I'd upgrade to a track heat upper as well.

Your heavy first will appreciate the stroke, plus your wallet won't get hit so bad.

Adam

 

fawcett

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Jan 18, 2007

#10

• Jan 18, 2007

• #10

Dude your hp/tq #'s seem really impressive seeing that you have only boltons and an extra 4 cubes over a regular 302. Are they rwhp or fwhp?
For the record I am not flaming you. My engine makes 340flywheel hp-overall the care makes less than 300rwhp. And yeah, even I am not impressed but I can beat the hell out of it and it gets me around.
Whatever happens atleast you have a set up. Get out on the road and enjoy it.
-fawcett

 

Pokageek

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#11

• Jan 18, 2007

• #11

They are flywheel #'s. Just shy 300rwhp and with tune I got the tq to 312rwtq. Depends on the factor you use - anywhere from .80-.85. I usually take say .83 as a factor. Considering I am wearing cats, not too bad, lol.

BTW, with the cam in it, it is the coolest sounding idle I have heard. I probably should just keep it and stop aggravating myself.

 

ProKiller

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Jan 19, 2007

#12

• Jan 19, 2007

• #12

stick with what you got. maybe a meth kit or some nitrous, but i wouldn't go messing with a 351w based engine if i had working combo already. as for stroking the 306 to say a 347, you still have the down time. if it was me, i would let well enough alone for the time being, get the rest of the car up to snuff, then think about a 408 down the road.

get some suspension stuff under there, maybe a t56 or something.