340 replacement block.. with a roller cam?

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MoparPowa

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recently read 340 rep blocks wont work with a roller cam, and neither does a R-block, keep in mind this is the 59 degree tappets, not a 48 degree block, with 48 it should be fine, the main problem being the close tappets next to a already beefed up block means no room for the spider to hold the roller tappets in, and you cant grind the block without hitting the water jacket, anyone confirm this? anyone built one? with a roller cam? Thanks.

Ryan
 
that's correct, for certain lifter types. Different manufacturers have different tie bars, and there are some that do clear. I built a 416 recently for a fellow who insisted on using a factory block, just because he (or his previous builder) ground thru his R block clearancing the tie bars. You really need to reaswearch the designs, and dont talk to salesman...they have said they clear for a while now.
 
hrmmm... care to elaborate on that? Id really like to take a 59-degree route with a 340 replacement block, but a roller cam seems the way to go for performance, and Im looking into a street/strip dealy. Something to take to shows, but be able to put the rubber to the ground and run mid to low 10s at the track. 48 degree blocks are a pain to build considering special cams, heads, etc. Id be doing drag, but was also considering doing something to the effect of circuit racing? not sure what to call it, F-1 but not so fast? :D its what my bro plans to do with his 64 and a half mustang, and I thought it would be cool to, so yeah, not sure as of yet, any suggestions? was considering a stroker, 418 ci with a 340 replacement block .040 over, with a 4" stroker crank, but then I get concerned about not being able to run high revs, which is kinda natural with the whole circuit racing deal, is a 48 degree worth the pain? with a procharger or something to the effect of that? high revs but you can still keep the power? 7500 would probably be the limit anyhow. Poor pushrod geometry is killin me here :p appreciate any help, and any comments if anyone has done this, or the circuit racin deal
P.S.> the build would be a 63-67 A-body most likely(65' Dart GT hardtop is my interest)

Ryan
 
MoparPowa said:
hrmmm... care to elaborate on that? Id really like to take a 59-degree route with a 340 replacement block, but a roller cam seems the way to go for performance, and Im looking into a street/strip dealy. Something to take to shows, but be able to put the rubber to the ground and run mid to low 10s at the track. 48 degree blocks are a pain to build considering special cams, heads, etc. Id be doing drag, but was also considering doing something to the effect of circuit racing? not sure what to call it, F-1 but not so fast? :D its what my bro plans to do with his 64 and a half mustang, and I thought it would be cool to, so yeah, not sure as of yet, any suggestions? was considering a stroker, 418 ci with a 340 replacement block .040 over, with a 4" stroker crank, but then I get concerned about not being able to run high revs, which is kinda natural with the whole circuit racing deal, is a 48 degree worth the pain? with a procharger or something to the effect of that? high revs but you can still keep the power? 7500 would probably be the limit anyhow. Poor pushrod geometry is killin me here :p appreciate any help, and any comments if anyone has done this, or the circuit racin deal
P.S.> the build would be a 63-67 A-body most likely(65' Dart GT hardtop is my interest)

Ryan
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It's when the valve lift becomes really high (combined with extended high rpm) that you see problems with the 59* tappets. I use a .640 lift solid roller and i turn the motor 7800 - 8000 rpm with no problems on the local dirt track here in fairbanks.

And with a longer stroked motor you can build your motor around the cubic inches. With a good 410 - 416 - 418 you should be able to keep the rpms well under 7500 and make plenty of power.

And to the OP, comp cams have come out with a solid roller tappet set made specially for the new 340 replacement blocks.
 
W2-340 said:
It's when the valve lift becomes really high (combined with extended high rpm) that you see problems with the 59* tappets. I use a .640 lift solid roller and i turn the motor 7800 - 8000 rpm with no problems on the local dirt track here in fairbanks.

And with a longer stroked motor you can build your motor around the cubic inches. With a good 410 - 416 - 418 you should be able to keep the rpms well under 7500 and make plenty of power.

And to the OP, comp cams have come out with a solid roller tappet set made specially for the new 340 replacement blocks.
Click to expand...

Not true! Those replacement blocks still have the extra head bolt bosses in the valley for 6 head bolt heads like W8-W9 and Indy's as well.
I helped design those lifters Comp now sells, and they will clear everthing in the block EXCEPT for the head bolt boss!!
You will have to cut or grind that boss...you can trim it down with a porting tool or just knock the majority of it out but be carefull as water sits just .200 behind the valley wall.

Once you do this, your smooth sailing. I can sell you those lifters far cheaper than Comp can when your ready...as well as a nice cam for your intended purpose.

Brian
 
ou812 said:
Not true! Those replacement blocks still have the extra head bolt bosses in the valley for 6 head bolt heads like W8-W9 and Indy's as well.
I helped design those lifters Comp now sells, and they will clear everthing in the block EXCEPT for the head bolt boss!!
You will have to cut or grind that boss...you can trim it down with a porting tool or just knock the majority of it out but be carefull as water sits just .200 behind the valley wall.

Once you do this, your smooth sailing. I can sell you those lifters far cheaper than Comp can when your ready...as well as a nice cam for your intended purpose.

Brian
Click to expand...

Yeah sorry i forgot to mention the extra head bolt provisions that need to be machined away to make clearance for the tie bars.

It's really neat you helped design those lifters Brian.
 
Member Korryliss found out the hard way years back before this issue was known about the replacement blocks. Search his name and ask for pictures if you do not see them so fast. I met him at a FABO meet in Ct. He had a army of pictures of his car build and the engine damages were not a preety site. He has plenty of shots of this issue.
 
Also, I've noted stock blocks can go preety far. Of course pushing the envolope is dangerous and pricey apon failure. A 48* block is worth it IF your racing and racing for the money. Expensive? What else is new in racing? Worth it? Extreme power levels can be had over the stock block much more safely with longer life.

A 48* block is probably not worth it for a street driven car unless your really looking to take no prisoners, just courpse's.
 
October issue of Mopar Muscle should put this issue to rest. I built a 427 inch stroker motor for the article with a 340 replacement block and used Comp roller lifters. All the pictures are in the magazine.
 
ou812 said:
Not true! Those replacement blocks still have the extra head bolt bosses in the valley for 6 head bolt heads like W8-W9 and Indy's as well.
I helped design those lifters Comp now sells, and they will clear everthing in the block EXCEPT for the head bolt boss!!
You will have to cut or grind that boss...you can trim it down with a porting tool or just knock the majority of it out but be carefull as water sits just .200 behind the valley wall.

Once you do this, your smooth sailing. I can sell you those lifters far cheaper than Comp can when your ready...as well as a nice cam for your intended purpose.

Brian
Click to expand...

Brian ou812,

How much are you selling those lifters for?

Regards, Chris
 
AndyF said:
October issue of Mopar Muscle should put this issue to rest. I built a 427 inch stroker motor for the article with a 340 replacement block and used Comp roller lifters. All the pictures are in the magazine.
Click to expand...

I just read that last night! Any insight on how it worked out? You did a fantastic job.
 
The 427 build worked out great. We used a small cam and carb and set the motor up to run like a Viper. We ended up with the same basic power curve as a third gen Viper. The motor went into a '68 Valiant and it really hauls the mail.
 
In an email I got from Shady Dell Ryan told me that some serious machine work is needed to fit the new Comp rollers in the 59* block, hmmmmm.........
 
I used a resto block with indy heads. I am running a 700 lift comp solid roller with mopar roller lifters. My block was cut on a cnc mill for the lifters. The lifter bores are alot taller on a resto.block. You can have the lifter bores keyed for custom lifters. Or have them milled down for shorter lifters.I Agree with the rpm input. I shifted mine at 8000 and Higher. I also shifted it a 7000 and 7500. Being over 400 cubes the motor likes the lower rpms. I love to twist the motor up to the extreme. So far mines taking the abuse like a champ.
 
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