Two Hemis and a brain teaser!

I need the opinion of people who know the value of HP gain based on an overbore and some early Hemi gurus on deck for general performance considerations.

Okay, here's what's going on. Read carefully!

I have two early 331 Hemis. The long term goals for the two engines are as follows:

Engine 1:
This motor will be built this year and is priority #1. Normally aspirated with a six Holley 94's that will go in my Model A and will be as close to a daily driver as possible. Looking for a 350 to 400 HP at the flywheel for this one, but I plan on it being more of a top end motor. No quarter mile or racing. Just a strong highway motor to get my Model A BRICK cutting through the wind.

I wouldn't be apposed to leaving it a stock 331 cube motor, but was originally thinking that I would need to knock it out +.120 to get the extra umph that I need.

The heads that will be used on this motor are 354 car heads. These must be used for this setup because of the 6x2 Offy intake I'm running. (water crossover provisions must be on the heads with this manifold)

I'm thinking 10:1 or 10.5:1 pistons will be needed in this case as well, along with a healthy cam to get it breathing.

Engine #2:
This is a low priority engine. This will be full blown motor and will be mostly just for fun. No real target on HP right now, but I would not be apposed to leaving it a small bored 331 blown motor. I have no heads for this motor or any other solid parts yet. Just a block basically.

This one is on the "5-year plan". I have no plans to buy anything for it right now, but am thinking long term since I have a block.

Okay, NOW you need to see the blocks I have to work with and you need to hear about their condition.

BLOCK #1:
This is out of a 1953 New Yorker. It looks gross but after stripping it down to the block looks to be just fine.



The one BIG issue and concern with this block was there was a broken rod. The big end split so the rod was dangling into the crank area. The crank in turn beat the hell out of the rod. Damage to the bottom of the cylinder from the rod was done. The piston was jammed almost at the bottom of the stroke when it happened so the damage was not in the compression area of the cylinder.

These blocks will take some abuse, but I'm curious to see how that cylinder mags out.

BLOCK #2:
This block is BEAUTIFUL! The bores look as if I could do a quick polish and drop in some pistons with .010 over rings and be done with it. I see absolutely nothing wrong with it and expect a clean bill of health from a mag and sonic check.




Okay. Now for the brain teaser part of this thread!

(we will ***ume both blocks check out just fine with no cracks)

I would suggest a quick reread of the goals for the two engines first before reading the questions.... A cup of coffee might be worth while as well.

The Questions!

#1) Can I achieve my target HP of 350 to 400 for the Engine 1 (normally aspirated) without a huge overbore like I'm contemplating?

#2) If I don't need to do a huge overbore on Engine 1 will I be okay with the extra volume the 354 heads offer?

#3) If the huge overbore is needed to get what I need out of Engine 1, what kind of life expactancy should I expect out this block since it will pretty much be at its largest overbore before getting into the water jackets? (***uming block also sonic checks okay and ***uming a 4000 mile per year max, and some occasional "horsing around")

**Now the MORE annoying question**
#4) Any thoughts on which block I should use for which based on everything I've mentioned?

And now, for Deep Thoughts...

I'm thinking that if an overbore is needed and BLOCK 1 checks out good on a mag and a sonic check, I should go with that one for a huge overbore since it has damage to the lower part of the cylinder anyway. Then I would use BLOCK 2 for a stock bore blown motor in the future.

If an overbore is NOT needed for Engine 1 then I'll run BLOCK 2 and take advantage of the fact that it will have a long life with the ability to have several overbores and rebuilds. Then I'll use BLOCK 1 as just a completely rediculous, overbored blown motor for the future.


Okay... let's hear what you think! I guess it all comes down to rather or not I need the large overbore to get the HP I need. I really want your educated opinions and suggestions on the matter and definitely some tips on a strong reliable semi-high HP street motor for daily use vs. general life span with the given conditions.

Thanks and you realize I put this up here just to get you guys thinking in the middle of the week!! And yes... I also realize the questions are somewhat broad.

 

I don't know much about Hemi engines but I would use the better of the 2 blocks for the driver. Or at least the one with the least amount of damage. I had to make the same decision on which motor to use when I rebuilt by 235 chevy for daily use. I picked the one that was the cleanest and the most worry free.

Thats just my oppinion...

 

I've been thinking the same thing. I have a feeling I can get the HP I'm looking for as well without the huge overbore just by good component selection. I'm only a little concerned about the 354 heads with that size bore.

So do any of you, with early Hemi experience, think a 331 with a semi-stock bore can be built to that kind of HP by component selection alone?

 

I'd agree with that.

I'd use engine number 2 for the Model A and engine number 1 for the blown monster!

I'm looking foreward to the build up of these engines. I've always wanted a HEMI!

 

I have a 54 331 in my NYDLX and it has never given me any trouble. But it is stock. I would suggest posting your questions on a Hemi thread. IMO I believe you can go either way, these are pretty damn stubborn engines to mess up.

 

Yeah, we're definitey not talkin' stock here. A stock 331 will not make that kind of horsepower.

I have faith in the good people of the HAMB! There are a ton of "Hemi Smart" people here! I don't see the need to go elsewhere with this. They're not really all that complicated for that matter either. I just need people with building and performance experience on these engines to tune in...

 

On the street engine... compression is important to reach the HP you want. The hemi is tolerant of more than a wedge by almost a whole point. More CID will help. What sort of Cam have you been thinking of?

 

I've been looking at an Engle cam, hydraulic series. Hadn't actually sat down and done the math yet though. I'm completely open to suggestions and opinions on profiles. I was thinking something fairly aggressive is a must. I think the 6x2 should provide enough CFM to make it happen as well when all six carbs are dumping.

I'm also not ruling out a solid lifter cam either. I have to buy all new lifters, pushrods, valves, springs, etc... so the sky is the limit and I'm planning on adjustable pushrods to help adjustability as well.

 

If you could post the block numbers and any symbols at the front of the valley would be helpful.Some had oversize lifters, just something to look out for.
John

 

The numbers from BLOCK 2 are C53-8-58625

The other block is barried in the back of my garage and I won't be getting to it anytime soon. I'll see if I can dig up a picture of the casting number though. I know for a fact that BLOCK 1 is out of a 53 Chrysler New Yorker 4-door, because I pulled it myself. I also dissasembled it myself and the lifters appeared to be standard size.

 

At that compression in California in the summer you may have pre-det problems with todays low octane fuel . Boosters may be in order . I've had issues with my 9.5:1 Poncho in the summer .

 

No symbols in there so your ok on the lifters they are standard.
John

 

Huge bore jobs on 331 hemis are far from unheard of, as the block was cast extra thick. I have heard of 331's being bored to 4 inches , though IOM. that may be a bit excessive. Im getting ready to do a 54 331 with .30 over 354 slugs. With the extra cubes and compression should go a long way to at least 400 horsepower. As long as the block checks out I would stick to your original plan.

 

So looking at cams, how does something like this sound:

.514" Lift
.343" Lift at cam
230*duration @.050"

How's my idle going to be?? Pretty "lumpy"? I'm totally fine with lots of lumps as long as I don't have to be on the pedal all the time at stop lights and such.

 

Scooter, I'm runnin 10.5 to 1 .030 over pistons with 6 94's and I fully expect at least 350 HP. Not built yet but I mocked it up last week

 

I like the original plan for the fact that extra cubes are guaranteed horsies, but I'm concerned about the driving I have in store. I intend on having this car around for awhile and doing some road trips and such. I'm afraid if I ever have to "freshen things up" that even a slight hone job may put in in the red zone for potential issues. I don't doubt for a MINUTE that if the core shift is okay and the sonic check tests out good that I can punch it out to a 354 with no problems, it's just later down the road if it were ever to need a hone job or something if I would be screwed.

 

That is one ***y lookin' motor man!! What are you running for a valve train? How about the rest of the components??

 

GREAT! Good to know! I know the other block has a similar number series. No funky letters or anything. Thanks for the input!!

 

What do you usually run? I ***ume at least 91, right? This is the reason I was fearful of going over 10:1. Det problems are no fun!

 

Hemis make plenty of torque why not not a clean up bore and build for good drivabilty and torque.
John

 

No objection to that idea, just weighing my options. I want to explore all my options before sending a block out for machining.

The most important thing to me is highway speeds. I'm really designing the car and everything in to be comfortable at highway speeds... and... uhum... a bit beyond!

 

Static compression isn't as important as effective cylinder pressure. That's where the cam comes in. If it has significant overlap, and I think yours will, it will bleed off cylinder pressure making the higher compression workable on the street. It'll make it less efficient at lower rpm but improve flow at the upper rpms. Is this going to be in front of a manual or and auto trans. Gotta plan your whole package to work together.

 

Well my 354 should be putting out about 350 hp, on you 331 I would get forged pistons, rebuild the rods with arp bolts, have it balanced. On the heads just mild port& polish, gasket match, good valve job with hard seats, possably new guides. I wouldn't go more than 10 to 1 unless you want to buy prem gas, get the MSD ready to run dist( work great & very adjustable), now on exhaust the tendency is to use 2 inch primary tubes, but thats really too big for this displacement, if making headers use 1 3/4 inch and expand the end to fit in the oval header openings( on blown 2 inch is ok) too big of tubes will kill the power on the bottom. On cam selection is a balance how nasty it sounds or max power and where you make power( low end or high winding) these motors make alot of tork so it should go great, if you Pm with cams you are thing of running I can run them through my dyno program and see what happends, I don't have it on my work computer anymore. I run the PAW 274 duration cam, sounds great seems to make good power( I need a looser converter and more gear- stock converter and 2.70 gears) but it goes down the freeway real good. With what I recommended shoud put you where you want. But others might have different suggestions. Also buy or borrow the Tex Smith Hemi Book, great advice in there! Good Luck!

 

Shooooot! A MANUAL, of COURSE! T-56 with a .62 second overdrive. Yes, I know 6th gear will be scarce, but at highway speeds I have options. And to dial in the gearing, I've taken it a step further and backed everything up with a quick change. It's either going to be a dream to dial in or a total NIGHTMARE!

 

As a reference I've got a Crower regrind on a stock cam. I used their 280HDP intake profile on both intake and exhaust. .221 degree duration @.050 and .461 lift. Using my four Stromberg setup and the 354 bored out to 4" for the 392 std pistons the math from my runs showed about 280 hp at the rear wheels. My compression was relatively low at 8.8 but the cranking cylinder pressure was embar***ingly low. It's working great with the 671 now and aboiut 7# of boost. I'm using a boost timing retard to live with street gas although it loves mid grade and up.

Edit: I should note with the bore I'm at 365 CID.

 

Some folks don't understand the three pedal thing. I'm running a cast case A833 O/D. Sure is fun to cruise past the high end yuppie cars on the intersate.

 

Gracias! When I got the scoops I put them on, sat back, drank beer and looked at it while giggling like a schoolgirl.

Rebuilt stock rockers, Adjustable pushrods, solid lifters, isky 505 cam - .505 lift /254 duration at 50 thou. /108 lobe sep.

other Notable engine features-

.030 over 10.5 to 1 Jahns Pistons

Stock rods with ARP bolts

ARP head and main studs

I am going to the new double roller timing set and coverted oil pump. But i'm using the stock water pump- Kanter will rebuild them and I don't like the look of the chevy.

I am undecided on whether or not I'm gonna ditch the stock oil filter.

I am planning on using a stock duel points distributer. I may swap it for a magneto, but we'll see. You know how everything changes as you go...

 

WOW! Lots of good info there! When I narrow down the cam choice, I'll shoot you some numbers and take you up on that offer!

I fully intend on some serious head work. They need guides for sure, not sure on the seats, may be hardened already, and I had definitely considered porting and polishing as well.

Another great tip on the exhaust! It will all be custom. I'll start with some flanges and work out from the heads. It's a clean slate. The loose plan so far has been to build lakes style headers with dumps so I can make a bunch a noise around town, but then close them up for more tuned performance on the highway. Was thinking dual 2-1/2" tubing back to some series 4 flowmasters (or whatever). I'm open to opinions there as well.

Again, I'm working on a clean slate and just starting to think about this stuff. Any and all input is fantastic! I have no idea what to expect from an early Hemi other than what people have told me and from what I read. Speaking of reading, I have the Tex Smith book as well as a couple others with some good info. Found some great stuff in a couple recent issues of Street Rodder as well.

Man, I love this place! Meeting of the minds for sure!

 

Ignition... it's been brought up in this thread. I was planning on running the Vertex HEI distributor. Anyone see a problem with that? Is there enough juice there? I know HP is the bottom line, but aesthetics is somewhat important on some level as well, of course. I thought the mag-look distributor was brilliant, but maybe it doesn't have good performance characteristics??

 

Scooter, you're one lucky man! Two hemis and can't figure out what to do with them. I wish I had such a problem. Luckily, you're in the right place. You probably need to hear from B*** and the guy that built the Green Grenade (sorry, can't remember his name). They were at the Roundup last year and have plenty of experience with these motors. I love the old hemis but hadn't seen any in years until I came across the HAMB but, then again I live in the south Texas desert and there ain't too many hemis laying around down here.
Anyway, just wanted to say good luck with these projects and I can't wait to see how this comes out. Hemis rule! Good luck..