[P@blo]

Is it possible to get 400 hp from unported D ports running street gas compression ratio and still retaining decent torque as well......Can anyone post combinations that are running this power or is it impossable to do without porting ?.....Cliff,Carbking,b-man,jim,warped, can you help a brother out

[screamingchief]

Easy enough IMO.

As long as those are the only requirements.

Even the RA III/IV appraoch that number "stock",just need to pick up a few HP/lbs.ft. here and there and your goal is met.

A stock 455 with 6X's and the right cam,intake,carb and headers,with good tuning should easily meet that challenge.

Impossible???

Not even close.

A little harder if were talking about RWHP numbers maybe...

[b-man]

Yes, it's possible.

Read what Cliff has to say in these threads, 400-cube engines are discussed here:

Thread 1

Thread 2

400-horse 400 engines can be built using the stock high-compression big-valve heads, shooting for compression of about 9.5:1 with 1970 #13 heads is a good way to get there. Pick a cam with 220 to 230 degrees intake duration depending on your gearing and transmission.

A 400 horse 455 is easy to build using stock 6X heads, about 9:1 compression is all you'll need. You can cam it a bit more aggressive than a 400, but you don't really need a huge cam or low rear end gearing for a street 455. A stock intake and Q-jet carb is fine for both 400 and 455 engines making 400 HP.

You can be conservative with these engine builds, just use the best quality parts (buy forged rods for sure) and machine work. The power is already there, it's just waiting to be unleashed by a well-chosen cam cam and good exhaust system. Don't forget that a PROPERLY jetted carb and ignition curve is essential, don't skimp on these two items.

[P@blo]

Yes b-man i forgot to mention it is 400 not a 455.....So with unported D ports running a cam like the Crower 60916 and a 9.3:1 compression it can happen

I forgot to say thanks for the posts

[Brian D'Amico]

More Info PLEASE!!!! Good Post!!! I'm thinking about scrapping the whole "stroker" project and building up my 400 the way the Pontiac Gods intended. I'm going to use eagle rods and JE or ROSS pistons, have it balanced and maybe do a slight port of the heads... I'm going to need some more info on what cam to use.. so if anyone has any info.. let me know.. (I was thinking about using the XE274 with Rhodes Lifters..) It's a TH400 auto with 3:36 rear and 670 heads. My thinking is.. with the higher duration cam, I'll gain the upper HP and with the Rhodes, I'll make up for the missing low end torque. I'm shooting for 9.5 to 10:1 ????????

[crkoester]

Off-topic note:

Brian, every time I come across a post of yours I ALWAYS catch myself doing a double-take at the pic of your car. It's spectacular. I've never seen such a great looking blue GTO, period.

Just had to say so....




Chris

[P@blo]

Brian I was also looking into a stroker kit but realized it is very expensive and seems to just move the power band down the RPM range....I figured that an original 400 with 1 hp per cubic inch will meet my needs for a street application and always liked how the 400's rev...I do have a 455 core from a 1970 GTO i will build much later in the future but want to wait on that project untill i can afford my dream motor.....for the 400 i was looking at theese parts and would like to avoid head porting because in my area all there is is chevy shops and when i hear them tell me Pontiac & Chevy is the same thing i run for the hills (heard horror stories about chevy guys ruining good Pontiac heads and would be more likley to get a set of E heads down the road):

# 64 heads milled to 80 cc
harland sharp full needle bearing roller rockers (1.5:1)
milodon mega flow valves w/solid bronze guides
Crower 68404 springs
Crower 60916 221/229 cam
Crower hyd. lifters
Melling m54fds ram air oil pump
hardend oil pump drive
Crane chromolly one peice push rods
felpro H.P. gaskets fp2806
double roller timing chain billet gears
Arp main studs for 2/bolt mains
Scat forged conn. rods
Sealed power forged replacment pistons
standard tension plasma moly rings
baffled oil pan w/full windage tray & crank scraper
Factory 1970 intake w/1" spacer
flow cooler high vol. water pump
1969 Q-Jet w 75jet/44b pri. rod

At 9.25:1 compression am i on the right track with this set up ?.....any information you would like to share would be very helpfull
Thanks, P@blo

[screamingchief]

Well,allowing some porting to be done to the heads does make the job here a WHOLE lot easier thats for sure!

I'd say shoot for around 250 CFM @ .500" lift(28"h20) on the intakes with the exhaust side around 75-80 % of that and you should make very healthy gains throughout the RPM range.

Use the best valves you can afford,get .100 longer stems so you gain some installed height over stock,this helps by allowing more lift to be used without any clearance issues arising,use these with Crower # 68405-16 springs @ a 1.7" installed height.

Be sure to have them slotted for 1.65 rockers,use this ratio and account for this with the cam,for a "find every HP" approach a custom ground cam will yeild the best results,consult with a pontiac specialist if you feel you need to,I'll give my recommendations in just a second.

The reason to employ the 1.65 rockers here is they give more lift with a slight increase in duration without any real negative impact in overall idle quality,kind of a bonus here,plus I feel it helps the throttle response a little myself.

Make sure to have the pistons set at zero deck for best results.

And with the 670's in use,you may want to consider laying back the chamber like the open chamber heads are,this helps unshroud the valves some and should gain a few CC's to help drop the CR slightly,still you may need to use a slight dish to get your final numbers where you want.

I myself would try to keep it under 9.5:1 but above 9.0:1 with iron heads,so it would be a good idea to have the heads done first so you know for sure what they CC at,then get the pieces for the shortblock incase you need a custom piston configuration.

As far as cam selection the choices are vast,final specs depend on the type of lifters to be used somewhat,I myself never recommend using the rhoads,especially with the XE style cams,but that's just me,I feel that when you decide to allow yourself the option of a custom ordered cam you have no reason to use them to "crutch" a less than optimum cam choice,I would use a solid lifter cam long before choosing the rhoads,JMO.

And the final cam choice will greatly be dictated by the stall your willing to run here,as with your combo I would say ideally you should stick around 2500-2600 rpm rated stall (you can get one that'll flash a little higher,but make sure its fairly tight for street use) so you wont generate too much heat at cruise in street trim.

I'm usually willing to give a little to gain a little so my choices are usually a little bit on the "stiff" side so a conservative person may choose a slightly milder choice for the sake of all around driveability,so you need to decide what is the primary goals for your combination.

For a std. hydraulic flat tappet choice I myself would use something like this:

Comp #51-000-5 xtreme energy lobes # 5446/5214
Specs; Rated dur. 278/292, Dur. @ .050" 234/244, Lobe lift .332"/.334", Lift @ 1.65 .547"/.551" and use a 112 LSA to smooth it out a little and spread the power band out,install it @/around 106-108 ICL.

This cam would be somewhere between the off the shelf 274XE and the 284XE parameter wise.

I'm sure it would have a fairly choppy idle,though it should be liveable for most part.

For a hydraulic roller,something like this:

Comp #51-000-0 xtreme energy hyd. roller lobes # 3315/3316
Specs; Rated dur. 282/288, Dur. @ .050" 230/236, lobe lift .340"/.347", lift @ 1.65 .561"/.572" and again use the 112 LSA and similar ICL position.

This one would fall somewhere in between comps off the shelf xr276hr and the xr288hr cams parameter wise.

And not to overlook the solid cam choices:

Comp #51-000-5 xtreme solid lobes # 6057/6089
Specs; Rated dur. 282/290, Dur. @ .050 244/252, Lobe lift .347"/.352", Lift @ 1.65 (not deducting for lash) .572"/.580",and again likely use the 112 LSA for the same reasons as previously noted.

Now I'm sure that there are plenty of other choices that will do the trick,thats where this gets intresting for sure,I just used these comp lobes for an example here.

Others will share their thoughts on this I'm sure.

[screamingchief]

By the way,I was mostly refering to Brians post in my last post.

Pablo (Brent) if I were you I'd seriously consider shipping those heads to someone who can really give them the attention they deserve,makes a huge difference in overall performance,not just low or high end performance,the difference can be substantial !

And my choice of the comp xtreme lobes is also why those cam choices appear to be somewhat larger than other choices,this is due to their design and a choice from other cam lines (even other comp choices) would need to be taken into consideration somewhat and adjusted accordingly.

[KEV]

P@blo,

Your parts list should get you to your goal no problem. I like the crower cam choice you made. I would not use Rhodes lifters with it tho as I don't feel that cam is big enough to require them. Another cam with similar specs is the crower 60242 that would work well.

I would probably do a little bowl blending and gasket match the heads as well.

Gearing this combo in the 3.55-3.90 range will work real well.

Kev

[Bill Eveland]

If you have Jim Hands book check out KRE's sample build up in the back of the book, it's a 406 and uses the Crower 60916 cam. I would think that combo would have the 400 horse.

[P@blo]

screamingchief,Pittburg,Kev,B-man,Brian,Crkoester...thanks for all your posts

Anyone know who can port Pontiac heads in Winnipeg Manitoba without ruining them?

[screamingchief]

Not in Winnepeg,but in Canada my recommendation is to contact SD performance (Dave Bisschop) ,they're over in Chilliwack,British Columbia.

Here's a link to their website:
http://www.sdperformance.com/

Everyone I've ever heard about having them do they're heads has had nothing but high opinions of the work recieved,and he is highly regarded in the pontiac community,and very reasonable price wise too,I feel you should get a very good end product from them.

[b-man]

Originally Posted by P@blo

Brian I was also looking into a stroker kit but realized it is very expensive and seems to just move the power band down the RPM range....I figured that an original 400 with 1 hp per cubic inch will meet my needs for a street application and always liked how the 400's rev...I do have a 455 core from a 1970 GTO i will build much later in the future but want to wait on that project untill i can afford my dream motor.....for the 400 i was looking at theese parts and would like to avoid head porting because in my area all there is is chevy shops and when i hear them tell me Pontiac & Chevy is the same thing i run for the hills (heard horror stories about chevy guys ruining good Pontiac heads and would be more likley to get a set of E heads down the road):

# 64 heads milled to 80 cc
harland sharp full needle bearing roller rockers (1.5:1)
milodon mega flow valves w/solid bronze guides
Crower 68404 springs
Crower 60916 221/229 cam
Crower hyd. lifters
Melling m54fds ram air oil pump
hardend oil pump drive
Crane chromolly one peice push rods
felpro H.P. gaskets fp2806
double roller timing chain billet gears
Arp main studs for 2/bolt mains
Scat forged conn. rods
Sealed power forged replacment pistons
standard tension plasma moly rings
baffled oil pan w/full windage tray & crank scraper
Factory 1970 intake w/1" spacer
flow cooler high vol. water pump
1969 Q-Jet w 75jet/44b pri. rod

At 9.25:1 compression am i on the right track with this set up ?.....any information you would like to share would be very helpfull
Thanks, P@blo

Looks to me like you should build almost exactly what you have listed. The 80cc heads should be perfect, if you ever get a load of bad premium fuel the engine should handle it without too much fuss. Upgrade to 1.65:1 rockers, they cost the same as the 1.5s and you can use the added lift and the couple extra degrees of duration @.050" they'll give you.

Not sure on carb jetting, I had mine worked over completely by Cliff so perhaps he could advise you on jets and rods. Better yet get one done by him, get it in early enough (or use one of his '76 and up late-model better cores) and it'll be ready when you are.

Definitely get your heads done by Dave at SD Performance, you won't find better quality. I have a set of Dave's ported 6X heads (260 cfm) that I have stashed for another project, beautiful work complete with flow sheets. Plenty of my friends have had engines and heads done by SD, you won't be sorry. A set of 240 CFM heads would more than do the job for you.

Here's a post I made some time back concerning a 406 I'm now finally putting together. I have accquired a 3.36 posi rear to use with this combo, I'm usually just running across town to go to work at 50 to 60 MPH, so I'll replace the 2.93 cogs I have in the car right now.

My street 400.

[Brian D'Amico]

Originally Posted by crkoester

Off-topic note:

Brian, every time I come across a post of yours I ALWAYS catch myself doing a double-take at the pic of your car. It's spectacular. I've never seen such a great looking blue GTO, period.

Just had to say so....




Chris

Chris... Thank You Very Much!!! It's been awhile since I've been behind the wheel due to my engine being rebuilt.. (May of 2005).. so it really makes me feel good to hear someone appreciate my Goat!!

Since you like that one.. (sorry P@blo.. didn't mean to bogart your post.. ) here's one more...



P@blo.. Why the Crower cam? Not that I'm knocking it.. just want some info on why you picked this one and stories of how it performs. Us "400" guys have to stick together!!

[chiphead]

The Comp XE274 cam is killer in a 400. I love the way mine runs. I've heard good things about the crower grinds too. I'm curious to see a comparison of the powerband on a given engine using the XE274 cam and whatever crower is closest to it. I'm curious what the tradeoff would be??

I'd say you'd need a really good set of stock D-ports if you wanted 400 HP without porting. The 670s have excellent low-lift flow, and decent high-lift numbers. Even then, I'd think that 208/180 CFM stock would be pushing it for 400 HP. I had mine ported to 236/193 @.500, and it wasnt that much porting needed. I'm still using the stock-size 400 intake port.

[screamingchief]

That crower would be a pretty good choice from the others experience/opinions on this,and "size" wise I feel it is in the neighborhood for most cams other than the comp XE series,I feel it should do the job here myself as well.

I used the comp lobes as an example to demonstrate what I would consider the "high-limit" for this type of deal while still attempting to acheive some sort of day to day "manners" in a "street" type combination,but as I pointed out,some are willing to accept what others may not,and in that case it will pay to err on the conservative side of choices.

Every combination is different,and a few small changes in one area will often require a few changes in other areas as well to achieve the best overall performance from a given combination.

For instance most all my more recent cars are manual disc cars,so idle vacuum is usually less of a concern to me than it would be for most,and I am usually willing to give up few lbs.ft. down low for the sake of being able to limit tire spin and pick up a few HP in the mid range.

This why most of my "personal" cam choices tend to employ tighter LSAs than most,but I wont generally recommend that for others as often they are not overly happy with the choppier idle and lower idle vacuum that they produce,but in my situation I use it to narrow down the power band and "aim" it at a specific RPM range via the ICL.

Cams like these MUST be degreed in to work properly,and often may need to be changed a few times to find the best overall ICL.

Also to use them effectively you also need to ensure a free flowing exhaust path to try and limit the low RPM reversion they can exhibit due to their design.

It all depends on how much you are after power wise,where you want the power band to be,and what your willing to live with in the way of overall ride quality.

And often many decisions are made to account for items already in place,such as gearing,convertors and/or transmissions,exhaust,intake/carb,and so on.

The combination pablo listed should achieve his goal with relative ease and little trouble,so what's not to like about that?

[screamingchief]

The crower I feel is closest to the comp XE274 would likely be their #60210 278HDP "hi-draulic hauler" it specs at:

rated dur. 278/288 , dur. @ .050 229/239 , lift @ 1.5 .480"/.501 , LSA 108

This is the cam I will be using in the 455 going into my '72 firebird,in a 455 its pretty liveable,but may be a little more "stiff" than most would like in a 400 due to the tighter LSA,but I would still have considered it if mine were a 400.

I have a friend with the comparable ultra-dyne grind on a 110 LSA in his 400 in his '77 grand-prix (mildly ported 6x4's milled .045) and it'll tear your head off for sure,it should be good for some mid 13's in that heavy car,but also you need to consider it has a 2400-2600 convertor and 3.90 gears though,as well as a torker I,and a 750 cfm demon carb.

He's dealing with the vacuum issue though,and will likely be addressing that soon but it can still be street driven,just gets a little "hard pedal" brake wise at stop lights.

[slowbird]

Our very simple and mild compbo that we ran for awhile should have been around 400hp out of our 406cid.
Stock 16 heads with a good vavle job
Performer intake
750 Q-jet
1 3/4 headers
Ultradyne cam (I cant remember duration specs exactly but) duration around 216 to 218 on the intake and low 220 something on the exhaust, lift was .454 with 1.5 rockers and L/S was 112
TRW .030 over pistons
stock rods with good rods bolts.
With that basic combo our Ventura ran 8.0s in the 1/8 and 12.8s in the 1/4. That works out to around 320hp at the wheels which should be very close to 400hp at the engine.
We did change the cam later on to a single pattern one that was 239 duration and .507 lift with a 108 L/S and the can ran 7.8s in the 1/8 and 12.5 in the 1/4. Nothing else was changed, just the cam.

[P@blo]

So the single pattern cam was faster...ummmmmmm
Thanks for all your help guy's