Changing my mind. Going to a 5.8L instead of a 7.5L

Topic: Changing my mind. Going to a 5.8L instead of a 7.5L (Read 5072 times) previous topic - next topic

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #15 – October 29, 2009, 01:20:07 PM

Outside of some heads and cams, not much will interchange between 5.0 and 5.8's anyway, but i do agree that to make a windsor sit up and bark like a real mean dog, you gotta spend a few bucks.

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #16 – October 29, 2009, 03:16:06 PM

put in a sprint car spec 358 v8, they are selling the left overs to racers lol 800 hp!!!

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #17 – October 29, 2009, 08:20:33 PM

302 parts on a 351 doesn't necessarily mean you'll make 302 power. However, I spent a lot of time in porting the 5.8 truck/van lower intake, the BC Broncos adapter and I ended up cutting open my HO upper plenum to work it over real nice.

I just took down a bolt-on '96 LT1 Firebird Formula the other night with my set-up...and every last part under my hood is either a junk-yard find or a left over...you can even re-use the front end accessory drive if you cut one water pump stud down.

But, I'm also running a set of ported Cobra GT40's that have been milled down to 59cc's combined with my "street/strip" port job. My cam is a super mild grind that is supposed to be SD friendly, so I'm suprised it's still making power at 4500+ rpm.

I've got lots of good tricks and tips for doing things on the super cheap if you've got the tools/time/ability.

Good luck,
Don

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #18 – October 30, 2009, 07:57:02 AM

Don, that cam you have listed in your sig SHOULD pull at that RPM and a little bit more judging from the specs listed for it on the Summit website.

http://www.summitracing.com/parts/CRN-444232?part=CRN-444232&autoview=sku

Should actually work VERY well with the other parts you have listed. Like I said; everything works together.

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #19 – October 31, 2009, 05:16:54 PM

Yeah that cam is a bit too mild for what I'm looking to do though...I got it with the intention of staying SD and it ran pretty nice before the MAF swap but I wanted more out of it.

I think it's a great cam for a daily driver and it makes a ton of torque, but the wide LSA and short duration@.050" keeps it from performing well in the 4k+ range.

At the track last night it couldn't really pull much past 4800....and at 5100-5200rpm I could feel it start to break up a little so I think an ignition upgrade is in order...as well as replacing the stock HO throttle body...lol.

-Don

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #20 – October 31, 2009, 06:59:07 PM

Don do you have good springs on those heads??? You could be flirting with valve flutter/float...

I'm running a stock ign system with a Crane PS 91 coil, mine will pull hard all the way to rev limiter(6400 with the nitrous chip)... I have dual springs on the TF heads good for .600 lift...

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #21 – November 01, 2009, 07:49:27 AM

The extra cubes of a 351 will make that cam seem smaller and the peak power RPM will be lower than if it were in a 302.

I too run a stock ignition setup (I use an MSD coil) and have no issues. My WOT shifts occur right at the 6000 mark.

Tom makes a very valid point. The stock GT-40 springs are good for a decent amount of lift but the spring rate and pressure at full open might be lacking -- especially on a spring that's seen some long miles.

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #22 – November 01, 2009, 04:26:00 PM

I doubt it's valve float, I bought the recommended springs for the cam and set them up to the correct installed height and pressures. That cam is specifically listed for the 351 so I don't think its an issue of a 302 cam not running up to advertised RPM in a larger engine.

I don't know, I'm running Autolite 764's gapped @ .044" and it ran great in warmer weather, but it's getting a little lazy in the cold. I just picked up a set of Autolite platinums one range hotter and I'll probably gap them down to .040". The dist. cap and rotor(of unknown age and origin) could probably stand to be replaced also. I am certain that it is something ignition related as richening it up just made it slightly worse. A stock temp thermostat might even make a little bit of a difference....20-25* cooler cylinder head temps might be affecting it a bit more in the colder weather.

Maybe I should stop hi-jacking this guys thread with my own ...lol.

Good luck to the OP,
Don

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #23 – November 06, 2009, 05:14:48 AM

He's all over the net asking the same questions that could be had with a 5 second search just about anywhere, So I think your okay.

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #24 – November 06, 2009, 10:20:04 PM

I have got most of the parts now. Just down to a few small things and I can start doing a swap.

Sick88Tbird: Did you use the stock 302 mounts from your sport? Or did you go custom?

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #25 – November 07, 2009, 04:40:00 PM

Quote from: 86caprirs;297873

I have got most of the parts now. Just down to a few small things and I can start doing a swap.

Sick88Tbird: Did you use the stock 302 mounts from your sport? Or did you go custom?

The stock mounts will physically fit...but they can't even hold up to the 165hp SO....I HIGHLY recommend a set of ChuckW's mounts...he sells 'em at a great price and it's a part that'll last forever(unless you live in the rust belt maybe).

Good luck,
Don

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #26 – November 14, 2009, 06:18:06 AM

Where do I find these mounts?

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #27 – November 16, 2009, 05:45:55 PM

From a member of these forums, he may even be in the vendors section, I'm not sure...user name is "ChuckW".

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #28 – November 16, 2009, 09:18:19 PM

Thanks

Changing my mind. Going to a 5.8L instead of a 7.5L

Reply #29 – November 29, 2009, 08:34:38 PM

So I had the usual breaking of the bolts in the heads from the front of the intake. So I am thinking of removing the heads and drilling 2 broken intake bolts and one broken exhaust bolt. Well I just found a set of GT40 X heads for sale. I wonder if I should not waste my time.