302 SD convert to 347 or swap in stock 351 carbed? Need Help

[highspeedpursuit]

Ok, here it is. I have an 86 with the original 5.0 with SD. I'm looking at doing at budget rebuild (it's tired) and was contemplating doing a couple of different auctions. Keep in mind I wanna get the most bang for the buck and really wouldn't mind the extra power. Here they are:

1.) Take the factory 5.0 buy a rebuild kit and put it back together.

2.) Take the 302, buy a 331 or 347 stroker kit with a really mild SD cam, rebuild it with a gasket/bearing kit and throw it all back together. I don't wanna switch to mass air. I've heard of quite a few that have changed cams with an SD car but how about the stroker kit? The car is not a daily driver. Bad fuel mileage is not a concern as I would just like to do some bracket racing.

3.) I have a completely disassembled 1978 351W out of an econoline van. It would need to be completely rebuilt and refreshened. I also know that there would be alot of extra conversion parts to drive like conversion headers, dizzy, manifold, blah,blah,blah. Then would I rip out all my GT40 intakes and efi and go carbed? This seems like the less practical option.

4.) Do the same as: 1.)Take the factory 5.0 buy a rebuild kit and put it back together and use the heads of off the 351W and toss the rest of it away. I've heard that these heads should bolt on no problem on the 302. However I also hear that changing heads on the 86 is a big problem because of the piston clearances. (Flat top?)

Anyone confused yet? Any serious opinions?

[5.0Droptop]

347 stroker trickflow HCI kit and mass air conversion. The conversion is easy.

[highspeedpursuit]

Do i really need to switch over? Like I said cheap as possible. Will a 347 work with SD? Everyone seems to say you can change the cam (even in this forum) with an SD car but what about bumpin up the cubes. I guess it would be no different than a 351 efi with SD.

By the time I buy a decent meter, piggy back wiring and a computer I'm looking at an extra 300-400 bucks. I've got the top end: Gt40 upper and lower, mac 70mm TB and 70 spacer, cold air just wanna freshen up the block. But I was looking at the cost of the rebuild kit (new pistons, rods, crank etc.) for the 302 and it was not that much less than the stroker kit.

I guess though I'll have to get someone to balance it either way right? What other machine work would I need to get done?

[Bluegrass]

The 351 heads are no benifit on the smaller block.
At 331/347, the stock cam/heads will make more torque but not much more hp and even then these will come in lower in rpm because the block still cannot breathe.
No matter what heads, you need to check for piston to valve clearence.
You may need larger injectors on the 347 if you use good heads and cam.
SD will trim 24 lb injectors but no larger.
IMO you are just not going to get what a 331/347 will make without putting good heads and a cam in place then tune the combination.
Better to go with a Kenne Bell blower even on SD and make close to 300 hp in stock trim and not change much of anything.

[highspeedpursuit]

thanks. very good info. so in that case do you think that the cost of the kenne bell would be about the cost of the stroker kit, cam, heads and mass air conversion? even with a kenne bell on the SD I'd probably need a rebuild anyway.

I may have to save more pennies.

[2000xp8]

Go with the 347, TW's, rpm II intake, good cam, 24's and convert to Mass air. Beating the crap out of a stock engine with a KB IMO is not a great idea. Go from the inside out, not the outside in. More like blown HG's waiting to happen.

If done right, you should be able to get 350rwhp out of the combo shawn and i suggested.

Save the boost for when the rest of the engine is done.

[tmoss]

6-9 psi dpes not lift heads and blow gaskets unless the heads are not torqued correctly. Now, detonation has to be considered and tuned for also. KB blowers are not cheap - get pricing together on all the different ways to go. Don't forget all the little stuff that adds up either.

Gotta pick which direction to go..........

[highspeedpursuit]

well i want cheap. I wanted to freshen up the block and thought it might be a good idea to spend the extra to get the 3331/347 kit now and keep upgrading everything else later instead of doing it twice. I just wanted to see if i could get a little extra uuummmpphh and stay with the SD for now.

Does everyone think that doing up the 351W is a waste of time? I could sell my EFI stuff to buy some of the parts. Or am I better off just staying with the 302 block?

[2000xp8]

I personally think if you aren't going with a 392, the 351 is a waste.

And i also am not a big carb fan. The a9l does a really good job of adapting in a fox, and though a carb sounds easier, sometimes it's not.

[highspeedpursuit]

well anyone know what I could possibly guess at for horsepower numbers if I rebuilt the 302 as is with a cam like the E303 and left everything else as is including the SD?.........all parts same as sig with a 70mm tb/spacer.

[2000xp8]

No heads?
If not, under 235rwhp.

[5.0Droptop]

dont want to use the e303 with sd. It dosent work well.

[highspeedpursuit]

heads make that much of a difference eh? What are the cheapest heads you can buy? Is it worth it to port the stock heads? I'd ditch the 86 heads and I've got either a set of 91 5.0 heads or the 351W heads, would that help?

[2000xp8]

Heads make all the difference. Figure you can normally get about 300rwhp NA out of a stock shortblock.
That's with heads, without them you'd be pressed to get 240rwhp.
So out of the 100 possible extra rwhp on a 5.0, 60rwhp comes from the heads.

Heads to look for:
afr 165's
TFS twisted wedges
Edelbrock rpms

Porting stock heads you'd be pressed to crack 270rwhp.
91 heads and 351 heads likely wouldn't make a big difference.
Go for the good stuff on the first try, this way you don't have to spend more money later.

[mindgam3]

351 heads on a 302 provide no power increase at all?