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.
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?
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.
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.
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?
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.
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
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
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.
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.
