Blacktop weakness

[Maxwedge]

I have read a few posts and there seems to be a reliability issue with the blacktop conrods at higher revs, and I think I read somewhere that the blocks are not as strong as the earlier ones? Is there a simple fix?
- Would exchanging the rods for earlier smallport/silvertop solve this problem?
-ARP rod bolts on the blacktop rods?
-or is the structural strength of the block a problem as well?
I am looking at options for replacing a bluetop for blacktop for rally applications keeping the engine reasonably stock but not compromising reliability as it will get a thrashing!!

[Bling]

Use the search function at the top of the page, this has come up 1,353,343 times so far, so you will find the info you need if you have the motivation to look

[Maxwedge]

Extremely motivated, just short of time!!

[Bling]

Blacktop block should be fine and silvertop rods are way better than blacktop strength wise so go for them as for ARP rods i'm not sure, with it being a rally car I think you need to do more research

[Maxwedge]

It just seems logical to use blacktop engines now as they are becoming available commonly at a low cost with lower ks than a silvertop.
I am interested to find out where in the rod assembly they have let go, whether it be the bolts or the rod itself?

[Bling]

they just snap in half I think

[Distrb]

I have read a few posts and there seems to be a reliability issue with the blacktop conrods at higher revs, and I think I read somewhere that the blocks are not as strong as the earlier ones? Is there a simple fix?
- Would exchanging the rods for earlier smallport/silvertop solve this problem?
-ARP rod bolts on the blacktop rods?
-or is the structural strength of the block a problem as well?
I am looking at options for replacing a bluetop for blacktop for rally applications keeping the engine reasonably stock but not compromising reliability as it will get a thrashing!!

The blocks are fine, nothing wrong with them

Just putting ARP rod bolts on the blacktop rods wont solve the problem as they snap roughly 1/2 way up the rod where they are at their thinnest. This comes about due to running at sustained high rpm (i'm talking +5krpm for 1000's of kms) thanks to the likes of circuit work/rally, when it fails, it'll try and punch holes in your block. Theres pics of the result in my project thread.

Silvertop rods are the logical replacement, with ARP rod bolts.

[RedMist]

I have read a few posts and there seems to be a reliability issue with the blacktop conrods at higher revs, and I think I read somewhere that the blocks are not as strong as the earlier ones? Is there a simple fix?
- Would exchanging the rods for earlier smallport/silvertop solve this problem?
-ARP rod bolts on the blacktop rods?
-or is the structural strength of the block a problem as well?
I am looking at options for replacing a bluetop for blacktop for rally applications keeping the engine reasonably stock but not compromising reliability as it will get a thrashing!!

The bluetop 3 rib blocks are supposedly weak, however all the remaining 4ages are of a similar 7 rib design and have a natively strong block.
You have to think about budget and what HP you want to produce. The smallport redtop is a great little engine thats well suited to rallying in highly modified form. However the 20 valves produce more power stock. And the 20 valves are considerably cheaper.