Ive posted this to a couploe mebers personally, but want as many opinions from expereince so here goes. Im gathering parts for my 454 .030 build, and having the hardest time choosing what to do with heads. Stock crank, stock rods with ARP hardware. Pistons are TRW forged L2349's which should get me to about 9.75-10:1 with a 118cc head. Cam Im pretty sure Im gonna go with the Lunati VooDoo 60204: 276/284; 233/241@ .050; .554/.572; 110 LSA. Intake will be a dual plane with a 750-850 carb. Th 400, 3000 stall, 3.73 rear . Primarily street occasional strip; not a daily driver.

My dilemma: I was convinced to use my 781 oval ports. Im looking at $1000 for all parts and mild port work including shipping or even if I go with local shop. Now Im sure it worth it and the machinists experience. But I can get a set of Merlin 269 ovals with SS vavle bronze guides etc whih list in Summit for $1439. I can sell my 781's which came running in elxcellent stock condition for $150 -200 Im sure and then Im only $239 more than rebuilding used head with Merlins? right? Am I thinking correctly on here? I dont mind spending the $$$ on my 781's if that is the best bang for the buck...but Im thinking maybe the merlins are? My question to all the Guru's on here is what would you do. Are the Merlins a better head out of the box than worked 781's etc? Opinions please and much appretiated Gentlemen.

That is a dilemma that is usually faced. The cost of machine work usually puts it close to buying new. However one positve is that you can pick what springs, and valves you want in the heads. If you buy a package you may not know what is in them. Both heads will be a good choice though. In fact the first series Merlin oval port head was modeled after the 781 casting open chamber head, I believe with a raised exhaust port.

I'm in the same situation right now as well, same pistons, cam, everything. My biggest question, price aside, is that World products head any good? There is so much on this site about bill mitchel/world products having low quality stuff, those heads just scare me a little.

Right now I'm contemplating 781's or the only other cast iron, new alternative.....the Dart Iron Eagle rec ports. They sell for $1400 under the Dart name brand and about $1250 under the Summit brand moniker.

Obviously, ovals are generally prefered for a street 454, but when you are talking about the new dart head the picture becomes fuzzy. They are rec ports, but it's a fairly small rec port (308cc) and they have a superior combustion chamber. I tend to wonder if it might be worth trying on a 10:1 compression 468 with the right cam and converter.

Bill

I'm also in the same position.
I am thinking that I will not put any more money in these 781's.
The weight savings will add to the performance potential, I am thinking.
When the time is right, I'm buying alum heads. Not sure wich ones yet though.

I've never had a problem with the bare parts. It's their machine work and assembly practices that I wouldn't trust. I ran a set of early rect port Merlin heads and they worked great. But I bought them bare and had them machined and assembled them at home. The block in my car is a Merlin II block and same thing, bought it unfinished and had my machine shop do it.

I think the Brodix Race Rites are a great head for the money! Plus they bolt right in. Exhaust ports are at stock locations which was great in a tight compartment like my Camaro.

Personally, I would go with the Dart 308 head. Key to it is some compression. Also, watch Ebay for GMPP ZZ502 heads. I bought new take offs for 1500.00/set and know of others that have gotten similiar deals.

PS - couple of things to keep in mind. TRW forgings typically do not have very deep (and sometimes not very wide) valve reliefs. You may be fine with a 2.25 intake valve, you may not. As a minimum, you will need to check with clay for P/V clearance. Point is, if the heads you end up with have 2.19" intakes, I wouldn't loose too much sleep over the thought of maybe loosing a few HP from not having 2.25's.

There's no way I would sink 1000.00 into old heads when there is other options out there.

Like Joe (and maybe b/c of Joe), I too got a set of those ZZ502 new take offs for 1500.00 to my door. Except mine came with a set of 300.00 roller rockers also. If you have some time or patience, just hang in there and keep a lookout. I gained about 1/2 point compression w/these heads, good flow, and knocked 75lbs off the front of the car.

Competition products has Canfields for a decent price, and I also like the Darts (Summit has them under there brand name also for a little cheaper)

have you considered AFR (AirFlow Research) heads?

Not sure if this will help ya but I had a pretty mild 454 stroker built with the Dart Iron Eagles, cam is a solid flat tappet 252in/261ex @50, Lift is 605in/615ex and its 10:1 compression. it did 624hp@6400 594ftp@4800 Here is a link to the Dyno sheet.
http://www.mnrollingthunder.com/newgallery/main.php?g2_view=core.ShowItem&g2_itemId=2763

Not sure if this will help ya but I had a pretty mild 454 stroker built with the Dart Iron Eagles, cam is a solid flat tappet 252in/261ex @50, Lift is 605in/615ex and its 10:1 compression. it did 624hp@6400 594ftp@4800 Here is a link to the Dyno sheet.
http://www.mnrollingthunder.com/newgallery/main.php?g2_view=core.ShowItem&g2_itemId=2763I think that those^ are some very impressive numbers for a naturally aspirated 454 engine with those moderate cam specs that you've listed.

I have a set of fully ported 990's on my motor. last year on my old 468 they made 687hp and 598ftp they flow good #'s and creat great hp #'s. But this was 13:1 with a 748in 731ex roller. 990's are a great head and you can usually get them for around $1200 fully ported and fresh.

Personally, I would go with the Dart 308 head. Key to it is some compression. .

Joe,

For a 454 like we are talking about here, what do you beleive the right compression to be? 9.5-10:1 OK for the Dart 308's with the 60204 cam?

I think people have been scared off by this head because the whole "oval vs. rec port" thing. But, we know how good the 990's perform on Chevy Crate motors with far less compression, cam and a older design combustion chamber.

Thanks,
Bill

Joe,

For a 454 like we are talking about here, what do you beleive the right compression to be? 9.5-10:1 OK for the Dart 308's with the 60204 cam?

I think people have been scared off by this head because the whole "oval vs. rec port" thing. But, we know how good the 990's perform on Chevy Crate motors with far less compression, cam and a older design combustion chamber.

Thanks,
BillHere's a good calculator that you can use to answer your question above^.....

http://www.hotroddersauctions.com/DynamicCompressionRatioCalculator.php

Lots of good replies guys...keep them comming.


To answer a few suggestions. Im sure the Race Rite's are good heads but your approaching 2K for the heads and every tech from Brodix Ive spoke to said they really only shine is you get the CNC package which puts you into the 22-2400 range. Im sure they are a good head but for what Im doing I just dont think I need them.

The Canfields Ive heard are a great bang for the buck but again Im into the 315cc range which I beleive is just too big.

I like the concept of the Summit heads which are dart Iron eagles. So back to the original questions which is the best bang for the buck and will give me the best fit for my application. Use the 781's and invest $1000 into them; or sell my 781's and buy The world 260 cc ovals ready to go out of the box for $1439; sell my 781's and buy the Dart Iron Eagles with the 305 runners under the Summit name ...but would these rectagualr ports and larger runners be too much. I look to the GM 454 425 hp motor and the 502...both respectable with rectagular port heads, but I question if they would have performed better with oval ports...My guess would be yes...the 572 with Oval port heads indicates this.

So Im back to original question:

781's worked for $1000

Merlin Oval Port 269cc's for $1439

Dart iron Eagle's (under summit name) 305 cc recagualr ports $1291.

There are a couple of nice things about going with the 781's. First off, you will get machine work done on them (such as a valve job) that will probably be better than an as cast merlin or dart head. Although the as cast merlin may flow a similar peak number to a cleaned up set of 781';s, Ill bet that the 781's will do better at low lift. Also, as has been stated, you can hand pick all of the parts to match your situation perfectly. I would spend the money on the 781's and sell them in the future if you want to go more radical. I also like the small runner in the 781 head over the 308cc dart. With the size of your cam, I think the dart will just reduce the responsiveness of the motor and not gain much on the top end. Any one agree or disagree?

Adam

I have the Dart Iron Eagle 308 heads on my 454 car runs great on the street hauls butt mine are early models that had teflon seals and ate the exhaust guides that has been fixed exh port raised # 6 spark plug wire is a challenge to keep from burning with 2" pipes. I made a 3/16 spacer flange from aluminum plate and the deck of the head must be thick they are HEAVY. They have spring options also. Need any other info?

just a FYI here.....with those pistons you mentioned, you'll have a 10.5:1 compression ratio with 118cc chamber heads IF you had the block zero decked. But if the pistons are .025" in the hole at top dead center, then that will give you a 10.0:1 CR (in case you didn't already know).

http://www.rbracing-rsr.com/compstaticcalc.html

just a FYI here.....with those pistons you mentioned, you'll have a 10.5:1 compression ratio with 118cc chamber heads IF you had the block zero decked. But if the pistons are .025" in the hole at top dead center, then that will give you a 10.0:1 CR (in case you didn't already know).

http://www.rbracing-rsr.com/compstaticcalc.html

Thanks for that info. The block has not been decked at all. According top TRW info catalog and via Summit it also stated that the 2349 pitons with 118.9cc head yeilds 10.18:1 compression ratio. Whichever heads I end up with I will CC the chambers and adjust them accordingly so all are close to each other and them play with gasket thickness to achieve compression I want. I was hoping to end up at 10:1 so I can run premium pump gas without any problems. thanks again for the info.

Bump. Would love more opinions and insight...anyone?

Raty (Bill). I am running 10.4/1 on my alum head motor. Cam is hyd roller 233/236, 112LSA installed at 108ICL. I have ran it on 87 octane (ran out of gas and this is what was in the gas can) with no detonation issues. My 408 motor had a Crane 286 flat tappet hyd 286/296, 226/234 112LSA/110ICL. Motor was 9.5/1 with iron heads. I ran that motor hard in 90*+ August heat, never pinged. I guess we have to remember that static compression is relative to the cam ICL. 4.25 stroke (on paper) need less static compression built in than a short stroke motor. JMHO, if I were to generalize what I have seen guys get away with for street motors with your basic performance cam it would be something like this. 396/402/427 motors shoot for 10.3 - 10.5/1, 454/502 motors, go 9.7-10/1 and 4.25 stroke motors can drop into the 9.5/1 range. Read enough combos on these pages and I think you will see this is what a lot of guys have settled into.

Guess what I am getting at is - within reason, I would rather build a motor with more compression and cut the timing a few degrees as compared to running low compression and then having to crank in a lot of added timing due to low cylinder pressure.

I can say that my 408 ran on 93 octane gas at about 10.5-1 with the 781 heads. It ran to 7000 without pinging.

http://www.sallee-chevrolet.com/frame.html?/Part_Finder/Navigaton.html

just an option, aluminum oval port heads for about $1800 complete

I think that those^ are some very impressive numbers for a naturally aspirated 454 engine with those moderate cam specs that you've listed.

I prolly should have mentioned that the heads did have a fair amount of work done to them...they really werent that cheap after the all the porting and the ferrera valves. I was a little disapointed in the torque numbers, if I were to do it over again I would go with AFR's.

I prolly should have mentioned that the heads did have a fair amount of work done to them...they really werent that cheap after the all the porting and the ferrera valves. I was a little disapointed in the torque numbers, if I were to do it over again I would go with AFR's.Ether way Brent, I think you did very well with that motor regardless of the amount of money you put into it. That's some respectable power out of a cam that isn't extreme. :thumbsup:

I prolly should have mentioned that the heads did have a fair amount of work done to them...they really werent that cheap after the all the porting and the ferrera valves. I was a little disapointed in the torque numbers, if I were to do it over again I would go with AFR's.

Have you ever had that car to the track?

Adam

Have you ever had that car to the track?

Adam


Yeah at the end of the year last year... the converter (Brand New) was completely shot, I was crossing the 1/4 mile at 6500rpm's at 119mph with only 3.73's and a 28" tire... way to much slippage. it was only running 11.50's & my 60' were only mid 1.8's at best, I do have a new converter that I'm throwing in this week. I'll probaby get out to the track in a couple of weeks...hopefully this stall will work a little better.

Cool, thanks. I'll be interested in what it runs.

Adam