Hot Rod Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Hey guys I tried posting earlier not sure what happened, not great at this forum stuff. So I'm finally getting around to starting my first engine build and hoping y'all could let me know if I have the right idea. It's a Pontiac 400 block out of a 67 catalina, I plan to get it magged, zero decked and stock bore possible. I'll use the stock crank and rods with new arp bolts, stock pistons if possible, fresh rings/bearings. For heads I plan to buy a set of KRE 74cc 270cfm aluminum d ports with .036 gaskets to get to 11:1 static compression. Cam is summit 2802 with 2224/234 [email protected] .050, .466/.488 lift, 114 lobe, hydraulic flat tappets, stock pushrods, 1.65 roller rockers, performer rpm intake w/ 750 quickfuel carb, summit longtube headers through summit 2.5" street exhaust. I'm hoping to hit around 450 hp/ 550 lb/ft do you think this combo will get me there? Does anything look obviously wrong or out of place here? Plan to run pump gas is this enough cam at this compression ratio to do so? I'll be running a m21 behind it w/3.73 posi. Thanks guys I appreciate it!
 

·
More for Less Racer
Joined
·
19,628 Posts
Pontiac V8 chamber design tends to noy be able to run as high on pump gas ans some other more common brands, 11:1 might be pushing it too far even with aluminum heads....might be better to shoot for 10.5:1 and play it safe.
I have no idea if the KRE head chamber is far enough removed from the original Pontiac design and shape to allow the higher compression.
Youhave a better chance of pushing the limit on compression ratio in something light, like a Gen 1 Firebird or 70's Ventura....a big heavy Catalina is not the best place to try it as it loads the engine heavier and rpm tends to climb more slowly,leaving it vulnerable to detonation.

But the big issue...SCRAP CAN the STOCK CONNECTINFG RODS....forget about even adding ARP bolts and resizing those CAST steel clunkers....get yourself an entry level set of sportsman style(more or less stock appearing style) aftermarket forged connecting rods.
The stock rods, no matter what you do to help them, are still far and away the weakest parts in the entire build. A bomb waitng in each cylinder for just a little too much rpm to set it off.

Stock cast pistons are also a pretty poor choice for a performance build. Forged would be a lot smarter, cast hypereutectic would at least be a better than stock choice.
 

·
Registered
Joined
·
1,598 Posts
If you do choose the hyper pistons , be acutely aware of the compression , hypers don't like to be rattled !!!
 

·
Registered
Joined
·
4 Posts
Discussion Starter #4 (Edited)
Pontiac V8 chamber design tends to noy be able to run as high on pump gas ans some other more common brands, 11:1 might be pushing it too far even with aluminum heads....might be better to shoot for 10.5:1 and play it safe.
I have no idea if the KRE head chamber is far enough removed from the original Pontiac design and shape to allow the higher compression.
Youhave a better chance of pushing the limit on compression ratio in something light, like a Gen 1 Firebird or 70's Ventura....a big heavy Catalina is not the best place to try it as it loads the engine heavier and rpm tends to climb more slowly,leaving it vulnerable to detonation.

But the big issue...SCRAP CAN the STOCK CONNECTINFG RODS....forget about even adding ARP bolts and resizing those CAST steel clunkers....get yourself an entry level set of sportsman style(more or less stock appearing style) aftermarket forged connecting rods.
The stock rods, no matter what you do to help them, are still far and away the weakest parts in the entire build. A bomb waitng in each cylinder for just a little too much rpm to set it off.

Stock cast pistons are also a pretty poor choice for a performance build. Forged would be a lot smarter, cast hypereutectic would at least be a better than stock choice.
Thanks for the advice I suppose the extra 800 bucks or so for forged rods/pistons is pretty cheap insurance. I should clarify, the motor came out of a catalina but it's going into a 68 bird would that make it more conducive to the higher compression? Another reason I want to shave the block is I've heard a tighter quench pad helps a lot of things but? Also KRE advertises their heads being able to run 11.5:1 on pump gas but that seemed unrealistic to me. And do you think I'll hit the 450 hp mark I'm shooting for or should I go for a little rowdier cam profile? Oh and I plan to gasket match the intake also. Should I try doing the same on the heads or is that a terrible idea? I do appreciate it
 

·
Registered
Joined
·
168 Posts
If nothing else, toss the pontiac cast rods. if you plan on "leaning" on this engine.
If it is going to be more of a cruiser that never see past 5000 rpm all that much . the rods are fine. but it sounds like you will be.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #7
If nothing else, toss the pontiac cast rods. if you plan on "leaning" on this engine.
If it is going to be more of a cruiser that never see past 5000 rpm all that much . the rods are fine. but it sounds like you will be.
Gotcha I don't plan to race every weekend or anything but definitely don't see myself keeping the pedal off the floor all the time hahaha yeah seems like those stock poncho rods don't have a very good rep. Thanks for the input
 
1 - 7 of 7 Posts
Top