First Time engine build - need 331 advice

68conv4sp · Oct 13, 2009

I have a roller block from an Explorer. I want to build it into a low stress, torque biased 331. I have Edel 1.90/1.60 (#60229) heads on my current 302 that I want to use.

Will they provide sufficient flow for a 331?

What 331 kit is the best - I am not worried about price at this point.

What compression ratio would be good - 10:1 or 9:1?

What cam would you recommend?

Thanks for the ideas.

70vert · Oct 13, 2009

subscribing, and lamenting the lack of roller cam Edelbrock Total Power Packages

I'd be on an Edelbrock Total Power Package for the 302/331 engine if they only had one. I've been looking at #2091 (with your 60229 heads) but can't figure out why they do one for the 351w with roller rockers and not for the 302w based engines - there are a ton of 302s out there. It seems like a good value, plug and play kit otherwise, but I'm sold on roller cam and lifters.

I could order the Edelbrock kit and substitute my own cam, lifters, and valve springs, but the value is lost.

I do have something useful for you - check out the Scat kits at CHP with forged cranks for a 331 stroker. You would probably split that block before a forged crank would be needed, but I just like the forged peace of mind. Lots of guys at the FordMuscle forums like Scat stuff: (this one has -20cc dished pistons)

SCAT-BASED Engine Kit - Ford 331 Reverse Dome -20.1cc

and you can pick your kit from CHP based on other factors.

I'd be interested to see what cam, rockers, etc, you choose.

68conv4sp · Oct 13, 2009

70Vert, thanks for the link. That kit looks very good. I was surprised at the 8.4:1 compression. I'm hoping for about 9.5-10 so maybe they would be willing to substitute a flat top piston.

70vert · Oct 13, 2009

Here's the link to all the 331 kits

It's somewhat poorly laid out - you have to look at the icon/avatar to see what is cast and forged, and from what manufacturer, for example, but you can search by Scat or Probe and then narrow down to what piston you want:

Ford Engine Kit - Ford 331 Stroker Kit, 302 Stroker

I didn't see 8.4 compression anywhere, that depends on the head of course, so you'll have to factor that in, but there's the whole list for ya.

68conv4sp · Oct 13, 2009

Well, I understood your terminology until the word "quench". Whats that?

D.Hearne · Oct 14, 2009

68conv4sp said:
I have a roller block from an Explorer. I want to build it into a low stress, torque biased 331. I have Edel 1.90/1.60 (#60229) heads on my current 302 that I want to use.

Will they provide sufficient flow for a 331?

What 331 kit is the best - I am not worried about price at this point.

What compression ratio would be good - 10:1 or 9:1?

What cam would you recommend?

Thanks for the ideas.

I don't know offhand how my Canfield 1.94/1.60 heads compare to yours, but I have had them on a 10.4 to 1 ratio roller cammed (Z303 with 1.7 rockers) 331 for about 5 years now. Great power and torque from 1500 rpms to 6500-7000. Intake is a dual plane 3x2 with Holley 250 cfm carbs. If you're looking at a daily driver, then I'd go with the lower comp ratio. Mine wants 93 octane fuel only. Kit was an Eagle with a cast steel crank, SIR rods, SRP pistons.

armand67Fstback · Dec 14, 2009

D.Hearne said:
I don't know offhand how my Canfield 1.94/1.60 heads compare to yours, but I have had them on a 10.4 to 1 ratio roller cammed (Z303 with 1.7 rockers) 331 for about 5 years now. Great power and torque from 1500 rpms to 6500-7000. Intake is a dual plane 3x2 with Holley 250 cfm carbs. If you're looking at a daily driver, then I'd go with the lower comp ratio. Mine wants 93 octane fuel only. Kit was an Eagle with a cast steel crank, SIR rods, SRP pistons.

I have some questions in regards to buidling a 331 also. I have a seasoned ~1970 302 and a 1991 5.0 Roller block, assuming both will be roller cammed, the older block would be retrofitted, which of the two blocks would be best/strongest?

D. Hearn, in California we only have 91 octane readily available, do you think I can run low 10 compression ratio and run 91 octane? If not with a carb, what about with EFI? Let me know what you think.

Thanks

D.Hearne · Dec 14, 2009

armand67Fstback said:
I have some questions in regards to buidling a 331 also. I have a seasoned ~1970 302 and a 1991 5.0 Roller block, assuming both will be roller cammed, the older block would be retrofitted, which of the two blocks would be best/strongest?

D. Hearn, in California we only have 91 octane readily available, do you think I can run low 10 compression ratio and run 91 octane? If not with a carb, what about with EFI? Let me know what you think.

Thanks

Go with the roller block.........hands down. Going roller in the 70 block is a deal killer. Too expensive to retrofit. My block is an 88 casting roller. Zero problems with strength, or anything else for that matter. You can likely get by with 91 octane and 10 to 1, When I first started mine up, the fuel tank was full of 87 fuel, it sounded like it was crushing rocks, so I drained it and have put nothing but 93 since, it's possible it will do with 91, but we don't have it here at the pump. I'd have to blend it myself to try it, so due to that, I never have.

rbohm · Dec 15, 2009

68conv4sp said:
I have a roller block from an Explorer. I want to build it into a low stress, torque biased 331. I have Edel 1.90/1.60 (#60229) heads on my current 302 that I want to use.

Will they provide sufficient flow for a 331?

What 331 kit is the best - I am not worried about price at this point.

What compression ratio would be good - 10:1 or 9:1?

What cam would you recommend?

Thanks for the ideas.

the edelbrock heads you have will do just fine on a 331.

as for compression ratio, i would shoot for about 9.5:1. the aluminum heads will allow a slightly higher compression ratio for the lower octane fuels, but you will still have to watch your ignition lead, and fuel mixtures.

as for the cam, select one that works in the 1000-5000 rpm range since you want a street engine. since you have the roller block look at roller cams, but a flat tappet cam will do fine as well.

armand67Fstback said:
I have some questions in regards to buidling a 331 also. I have a seasoned ~1970 302 and a 1991 5.0 Roller block, assuming both will be roller cammed, the older block would be retrofitted, which of the two blocks would be best/strongest?

D. Hearn, in California we only have 91 octane readily available, do you think I can run low 10 compression ratio and run 91 octane? If not with a carb, what about with EFI? Let me know what you think.

Thanks

D.Hearne said:
Go with the roller block.........hands down. Going roller in the 70 block is a deal killer. Too expensive to retrofit. My block is an 88 casting roller. Zero problems with strength, or anything else for that matter. You can likely get by with 91 octane and 10 to 1, When I first started mine up, the fuel tank was full of 87 fuel, it sounded like it was crushing rocks, so I drained it and have put nothing but 93 since, it's possible it will do with 91, but we don't have it here at the pump. I'd have to blend it myself to try it, so due to that, I never have.

i disagree with DH in regards to retrofitting a roller cam to a non roller block. there are retrofit roller cams available for the same money as other roller cams, and they work nicely with factory roller lifters. you just need the retrofit kit which is cheap enough to deal with.

but i will say that if you have a choice a roller block makes installing a roller cam a bit easier, and there is little difference in strength.

rebel65 · Dec 15, 2009

i've got ~10.5 : 1 on my 392 and i run 91 octane with aluminum heads.

D.Hearne · Dec 15, 2009

rbohm said:
i disagree with DH in regards to retrofitting a roller cam to a non roller block. there are retrofit roller cams available for the same money as other roller cams, and they work nicely with factory roller lifters. you just need the retrofit kit which is cheap enough to deal with..

Which cams are these? I've yet to see one that cost less than around $350 for the cam. Then you've got to buy custom length pushrods too. You can buy std base circle, off the shelf rollers for less than $100. And if you're not planing to spin it over 6 grand, you can use em with used factory lifters. Can't get any cheaper than that.

armand67Fstback · Dec 16, 2009

Thanks everyone for sharing your set ups and knowledge, I think this will help me choose engine components that I can enjoy and that will offer dependability.

rpk · Dec 16, 2009

check out The Mustang Depot. They offer very competatively priced kits for Fords. They offer a nodular iron crank that is between a cast and forged crank.Also they offer pro comp aluminum heads assembled for under $700. Go with the roller block. ARP head,main cap and rod bolts are a must!
In the October 2009 issue of Muscle Mustangs and Fast Fords they did a budget build up using a 5.0 block,pro comp aluminum heads with 210cc intake,70 cc exhaust,2.02/1.60 valves,64cc combustion chamber milled down to 60cc,pro comp funnel web single plane intake(I'd go with a dual plane for street),trick flow cam(.499/.510 lift,221/225 duration and112 lobe angle and a 750 holley double pumper.
The dyno chart showed 399 hp at 6,000 and 363 lb-ft at 5200. With the single plane the torque would have been at a lower RPM. Although the torque was over 350 from 4600 to 6,000. If you go with a 331 the numbers will be more favourable. Good luck

70vert · Dec 18, 2009

armand, I'm having my original '70 302 block done as a 331 roller with AL heads, forged crank, roller rockers, 9.5:1 compression or so. We've exchanged PMs, but I'm happy to compare notes as I go along. I do like that the '70 block is a bit heavier, but I'm not at all certain that all the weight is in useful places compared to the later roller block. But, it's the original block that came with the car, so I'm getting it worked on. Numbers matching is a nice plus.

The shop doing the build didn't mention that going roller on this block would be overly expensive, and they're going with a 2-piece rear main seal and 1.6 roller rockers, Eagle forged crank, h-beam rods, and of course roller hydraulic lifters. Oh yeah, a multi-layer steel head gasket too that will let them fine tune the final compression by custom ordering the thickness. Those are the details I have right now, I'll let you know more in January when I have more.

I'm with rbohm on the compression, and these guys echoed it. They don't like to go over 9.5, 9.8 at the most on a street engine.

One question I might have is what sort of parasitic loss will I have by reusing my original oil pan? I want to go with a Cobra-style T-pan, but I'm worried it's going to hit my Steeroids rack, specifically the hard lines on top of the power steering ram. I want to use reuse my original oil pan on the motor to mock it up and see how everything fits. I have measurements from another Cobra T-Pan, so once I see the clearance I'll know if the Cobra will fit. How much power am I gonna lose from oil slosh, windage, etc., from the OEM pan versus a Cobra aluminum t-pan?

woodsnake · Dec 18, 2009

Have you looked at a windage tray for your pan?

70vert · Dec 19, 2009

I'm looking at windage trays now, shop doesn't want me to swap pans

not to hijack the thread on armand, but the shop doesn't want me to swap pans - they want to make sure the oil pump pickup works well with the pan I'll use, which I understand and respect. I'll probably try the Cobra-style T-pan, and if there's any interference at all spacers can be used on the engine mounts or power steering lines could be moved slightly. It also means I probably won't be able to use the Ron Morris drop motor mounts, so I'll have less room to play with for header clearance.

I called NPD to see if they had the "Cobra" aluminum t-pan without the lettering, which they show in their latest catalog, but there's no ETA. It looks like I'll have to pay $50 just because it says "Cobra" . . . which is a little played out on a Mustang with no cobra or cobra jet heritage IMHO.

rbohm · Dec 19, 2009

70vert, how about using this pan instead?

Milodon 30925 - Milodon Street and Strip Oil Pans - Overview - SummitRacing.com

i will use one like this in my stang when i get to that point.

68conv4sp · Dec 19, 2009

I used that Milodon pan with the specific Milodon pick up. I also have the Ron Morris 1/2" drop mounts. It works well, and is not nearly as low as my sub-frame connectors or tri-y header flanges. A good fit overall.

70vert · Dec 20, 2009

That's a nice pan . . .

I like it, and the hump at the rear looks like a great idea for clearance, but I like the T-pan styling that matches finned valve covers, and the oil control in the t-pan. There are doors in the "T" kickouts that keep all the oil from flowing to the outside under hard cornering - they open on one side when you're cornering - the oil flow opens the door on one side and closes the door on the other side so there's always oil down at the bottom in the center. The oil that collects in the "T" gets cooled a little by the finned aluminum that surrounds it. At least in theory, it's a nice design.

If it doesn't fit, though, that Milodon is a great shape for a Mustang.

D.Hearne · Dec 20, 2009

rbohm said:
70vert, how about using this pan instead?

Milodon 30925 - Milodon Street and Strip Oil Pans - Overview - SummitRacing.com

i will use one like this in my stang when i get to that point.

I'm using an ebay knockoff of this pan on the 331 in my Comet. It's the only style of front sump pan that clears a main girdle's rear main studs due to the contour of the rear wall.

First Time engine build - need 331 advice

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