Refresh 331 Ford with head and possibly cam upgrade

[blackford]

I currently have a 331 SBF that has the following:

'68 302 block .030 over
'70 351w heads that have been heavily ported with 1.94/1.6 valves...never flowed
Comp cams 282S SFT cam 236/236@ .050 .528 lift. Tight lash set to .015
Probe 1.7 shaft rockers...increased valve lift to .561
Victor Jr intake port matched to heads
750 cfm HP Holley
KB322 Hyper flat top pistons with valve reliefs (383 SBF stroker piston). Pistons .005 in the hole
9.7:1 compression
.039 thick (torqued) Felpro head gasket. .044 quench
H beam Ford 289 rods 5.155 length
Scat Hi Nodular crank
Dougs stepped tri-y headers port matched to exhaust ports
Engine balance within a nats ass of zero tolerance

Car that its in makes 370 RWHP @ 6500. Crank HP is estimated to be 425 to 430 HP. Usable HP to 7200...down only 30 HP at 7200

I built it over 10 years ago and i'm refreshing the entire '65 FB Mustang with new aftermarket brakes and some other upgrades.

I was considering AFR Renegade 185 heads milled to raise compression to 10.5:1 to 11:1

I might consider a different cam also, but if I can leave the short block alone i'd like to do just the heads. Cam recommendations taken though.

Do you think the head change and raising the compression 1 point will get me to an additional 40+ HP?

[Casper393W]

I would most definitely say that you would see a 40hp gain with those two changes... AFR 185's work great on 331/347/351 combos....

[cv67]

x2 definitely worth it.

[Carnut1]

It really depends on how well the old heads were done and how well the cam matched the combo.

[blackford]

It really depends on how well the old heads were done and how well the cam matched the combo.

Given the results, I think the heads were done well. Flow is probably 240 cfm max given other 351w head porting results. My ports are 160 cc's intake and 60 cc's exhaust. I was very aggressive when I ported them.

The AFR 185s have max flow of 280 to 290. Mid lift flow is probably a lot better too. I know the cam has to be in concert with the heads to really take full advantage of them...thus i'd like to hear from anyone who would recommend a different cam.

[mag2555]

If your making 430 hp and you add 40 you will be pushing on those stock main caps and main webs darn hard!

[Carnut1]

It really depends on how well the old heads were done and how well the cam matched the combo.

Given the results, I think the heads were done well. Flow is probably 240 cfm max given other 351w head porting results. My ports are 160 cc's intake and 60 cc's exhaust. I was very aggressive when I ported them.

The AFR 185s have max flow of 280 to 290. Mid lift flow is probably a lot better too. I know the cam has to be in concert with the heads to really take full advantage of them...thus i'd like to hear from anyone who would recommend a different cam.

If you are rich buy new heads and have fun. Save the old heads for a work truck. Be sure to go through new heads and check valve stem clearance, valve seat runout and spring load.

[Carnut1]

If your making 430 hp and you add 40 you will be pushing on those stock main caps and main webs darn hard!

Stress test it.

[blykins]

A '68 is among one of the strongest factory 302 blocks, next to the older Mexican 302 blocks and the Boss 302.

I wouldn't have any issue with leaning on that block up to 500 hp.

Prep, component choice, and tuning has a lot to do with how long they will live.

I've got a customer that I built a little bracket 347 for. It dyno'd at 486 hp 8 years ago. It's stuck down in a Fox Mustang with a 5-speed and 4.56 gears. Launches at 5500, shifts at 7000. Finally came back this year for a freshen up. Would have went longer but he had a blown power valve and didn't notice....washed the cylinders down. It's a good thing all that happened because one of the rod journals was cracked too....

Bearings looked pretty good considering all the gas that went through them and the main caps showed no signs of fretting.

The block is a late model 5.0 roller block. Had ARP main studs and a DSS main girdle. I really don't put much stock into the girdle helping things, but it is on there, so I had to mention it....

I kept the same camshaft and heads, but added a point of compression, a different ring pack, and another intake manifold and added another 44 hp and as much torque. We'll see how she holds up.

[Carnut1]

A '68 is among one of the strongest factory 302 blocks, next to the older Mexican 302 blocks and the Boss 302.

I wouldn't have any issue with leaning on that block up to 500 hp.

Prep, component choice, and tuning has a lot to do with how long they will live.

I've got a customer that I built a little bracket 347 for. It dyno'd at 486 hp 8 years ago. It's stuck down in a Fox Mustang with a 5-speed and 4.56 gears. Launches at 5500, shifts at 7000. Finally came back this year for a freshen up. Would have went longer but he had a blown power valve and didn't notice....washed the cylinders down. It's a good thing all that happened because one of the rod journals was cracked too....

Bearings looked pretty good considering all the gas that went through them and the main caps showed no signs of fretting.

The block is a late model 5.0 roller block. Had ARP main studs and a DSS main girdle. I really don't put much stock into the girdle helping things, but it is on there, so I had to mention it....

I kept the same camshaft and heads, but added a point of compression, a different ring pack, and another intake manifold and added another 44 hp and as much torque. We'll see how she holds up.

I like using studs on a 2 bolt main that will be stepped on. I always check to see if if the block needs to be line bored or honed. I feel the couple bucks for studs is worth it.

[blackford]

I did use ARP main studs when I built it. Some people say that rpm is what can kill a block. If the balance is off, I can see how this would be true. My balance was done to zero tolerance by Superior Automotive in Placentia CA. That's what they claim anyhow...nothing is perfect, but they got it as close as they could.

I rev it to 7200 all the time. I hope to get a few more rpm out of it...say 7500.

The 282S Comp cam was advertised as 2000-6000 which of course can vary quite a bit based on the size of the engine and other factors, but in any case, the engine currently peaks HP at 6500 and HP is down only 30 HP at 7000. I suppose the .015 tight lash that I run it at and the 1.7 rockers could be making the cam a tad bigger. The 236@.050 duration was based on .015 lash so the cam should be 236@.050 the way I have the lash set up.

I had Moneymaker racing's Alex Denysenko once tell me, before he passed away, that you can run that cam in a Ford even tighter than .015 but i've never gone below .015 lash.

[bigjoe1]

I have seen WAY more than 40 hp with an AFR head change alone- Heads and cam can be 70 to 80 MORE HP




JOE SHERMAN RACING